Ethylene copolymer composition

ABSTRACT

Ethylene copolymer compositions comprise: an ethylene/α-olefin copolymer component comprising at least one ethylene/α-olefin copolymer having a density within a specific range, a melt flow rate (MFR) within a specific range, an amount of an n-decane-soluble portion within a specific range and a melt tension (MT) that satisfies a specific relation with the MFR; and a (co)polymer component comprising one (co)polymer selected from the group consisting of a low-density polyethylene obtained by high-pressure radical polymerization, a crystalline polyolefin and an olefin elastomer. The ethylene copolymer compositions are excellent in heat stability and moldability, and able to form films of high transparency, high mechanical strength and anti-blocking resistance.

This application is a continuation of application Ser. No. 08/077,352,filed Jun. 16, 1993, now abandoned.

FIELD OF THE INVENTION

The present invention relates to ethylene copolymer compositions, moreparticularly to ethylene copolymer compositions which show higher heatstability and moldability as compared with conventional ethylenecopolymers or ethylene copolymer compositions and from which films ofhigh transparency, high mechanical strength and high blocking resistancecan be formed.

BACKGROUND OF THE INVENTION

Ethylene copolymers have heretofore been molded by various moldingmethods, and used in many fields. The requirement for thecharacteristics of the ethylene copolymers differs depending on themolding methods and uses. For example, when an inflation film is moldedat a high speed, it is necessary to select an ethylene copolymer havinga high melt tension compared with its molecular weight in order tostably conduct high speed molding without fluctuation or tearing ofbubbles. An ethylene copolymer is required to have similarcharacteristics in order to prevent sag or tearing in blow molding, orto suppress width shortage to the minimum range in T-die molding.

Further, in extrusion molding, it is important to have small stressunder high shearing during extrusion in order to improve quality ofmolded article and reduce electric power consumption at molding.

On the other hand, Japanese Patent L-O-P Nos. 90810/1981 and 106806/1985propose a method for improving moldability by improving the melt tensionand blow ratio (die/swell ratio) of ethylene polymers obtained by usingZiegler type catalysts, especially a titanium type catalyst.

The ethylene polymers obtained by using a titanium catalyst, however,especially the low density ethylene polymers generally have problemssuch as their broad composition distribution and stickiness of theirmolded articles such as films.

Of the ethylene polymers prepared by using the Ziegler type catalysts,those obtained by using chromium type catalysts are relatively excellentin melt tension but have a defect of poor heat stability. This isthought to be caused by that the chain terminals of the ethylenepolymers prepared by using the chromium type catalysts tend to becomeunsaturated bonds.

It is known that the ethylene polymers obtained by using a metallocenecatalyst from among the Ziegler type catalysts have merits such as anarrow composition distribution and a low stickiness of their moldedarticles such as films. However, it is described in, for exampleJapanese Patent L-O-P. No. 35007/1985, that an ethylene polymer obtainedby using a zirconocene compound formed from a cyclopentadienylderivative contains one terminal unsaturated bond per molecule, andhence this ethylene polymer is presumably poor in heat stabilitysimilarly to the above-mentioned ethylene polymer obtained by using thechromium type catalyst. Further, because of its narrow compositiondistribution, this ethylene polymer might show poor flowability duringthe extrusion molding.

Accordingly, the advent of ethylene polymers having a small stress underthe high-shear region, a good heat stability, a high mechanical strengthand a narrow composition distribution will industrially be of greatvalue.

The present inventors have earnestly studied in the light of thecircumstances as described above. As a result, they have found that theethylene/α-olefin copolymer obtained by copolymerizing ethylene with anα-olefin of 3 to 20 carbon atoms in the presence of a specific catalystfor olefin polymerization has a density, a melt flow rate (MFR), atemperature (Tm) at which its endothermic curve measured by adifferential scanning calorimeter (DSC) shows the maximum peak, a flowindex (FI) and an amount of a decane-soluble portion in the specificranges, and the melt tension (MT) at 190° C. and the melt flow rate(MFR) satisfy the relation MT>2.2×MFR⁻⁰.84. The present inventors havealso found that such an ethylene/α-olefin copolymer A-1! as mentionedabove is excellent in melt tension and heat stability and has a narrowcomposition distribution. However, the ethylene/α-olefin copolymer A-1!is not always well-balanced between the melt tension and theflowability, so that a problem sometimes occurs when the copolymer issubjected to extrusion molding to form a film.

The present inventors have further studied and found that the followingethylene copolymer compositions (1) to (4) are excellent in heatstability, melt tension and flowability under the high-shear region, andfilms obtained from these compositions are excellent in transparency,mechanical strength and blocking resistance.

(1) An ethylene copolymer composition comprising the aforesaidethylene/α-olefin copolymer A-1! and a specific low-density polyethyleneB-1! obtained by high-pressure radical polymerization.

(2) An ethylene copolymer composition comprising the aforesaidethylene/α-olefin copolymer A-1! and a specific crystalline polyolefinB-2!.

(3) An ethylene copolymer composition comprising the aforesaidethylene/α-olefin copolymer A-1! and a specific olefin type elastomerB-3!.

(4) An ethylene copolymer composition comprising an ethylene/α-olefincopolymer composition and a specific low-density polyethylene B-1!obtained by high-pressure radical polymerization, said ethylene/α-olefincopolymer composition comprising an ethylene/α-olefin copolymer A-2!having physical properties similar to those of the aforesaidethylene/α-olefin copolymer A-1! and an intrinsic viscosity η! in thespecific range and an ethylene/α-olefin copolymer A-3! having physicalproperties similar to those of the aforesaid ethylene/α-olefin copolymerA-1! and an intrinsic viscosity η! in the specific range.

Further, the present inventors have found that an ethylene/α-olefincopolymer A-4! obtained by copolymerizing ethylene with an α-olefin of 3to 20 carbon atoms in the presence of a specific olefin polymerizationcatalyst which is different from the aforementioned olefinpolymerization catalyst has a density, a melt flow rate (MFR), atemperature (Tm) at which its endothermic curve measured by adifferential scanning calorimeter (DSC) shows the maximum peak and anamount of its decane-soluble portion in the specific ranges, and themelt tension (MT) at 190° C. and the melt flow rate (MFR) satisfy therelation MT≦2.2×MFR⁻⁰.84. The present inventors have also found thatthis ethylene/α-olefin copolymer A-4! is excellent in heat stability andhas a narrow composition distribution.

As the result of further studies, the present inventors have found thatthe following ethylene copolymer compositions (5) to (8) are excellentin heat stability and melt tension, and films obtained from thesecompositions are excellent in transparency, mechanical strength andblocking resistance.

(5) An ethylene copolymer composition comprising the above-mentionedethylene/α-olefin copolymer A-4! and a specific low-density polyethyleneB-4! obtained by high-pressure radical polymerization.

(6) An ethylene copolymer composition comprising the above-mentionedethylene/α-olefin copolymer A-4! and a specific crystalline polyolefinB-2!.

(7) An ethylene copolymer composition comprising the above-mentionedethylene/α-olefin copolymer A-4! and a specific olefin type elastomerB-3!.

(8) An ethylene copolymer composition comprising an ethylene/α-olefincopolymer composition and a specific low-density polyethylene B-4!obtained by high-pressure radical polymerization, said ethylene/α-olefincopolymer composition comprising an ethylene/α-olefin copolymer A-5!having physical properties similar to those of the above-mentionedethylene/α-olefin copolymer A-4! and an intrinsic viscosity η! in thespecific range and an ethylene/α-olefin copolymer A-6! having physicalproperties similar to those of the above-mentioned ethylene/α-olefincopolymer A-4! and an intrinsic viscosity η! in the specific range.

Thus, the present inventors have accomplished the invention.

OBJECT OF THE INVENTION

It is an object of the present invention to provide ethylene copolymercompositions which are excellent in heat stability and melt tension andfrom which films of high transparency, high mechanical strength and highblocking resistance can be obtained.

SUMMARY OF THE INVENTION

The first ethylene copolymer composition according to the presentinvention is an ethylene copolymer composition comprising:

A-1! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms having such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT>2.2×MFR.sup.-0.84,

(v) the flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation

    FI>75×MFR, and

(vi) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation, in the case of MFR≦10 g/10min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-1! a high-pressure radical polymerization low-density polyethylenehaving such properties that

(i) the melt flow rate (MFR) is in the range of 0.1 to 50 g/10 min, and

(ii) the molecular weight distribution (Mw/Mn, Mw=weight-averagemolecular weight, Mn=number-average molecular weight) measured by GPCand the melt flow rate (MFR) satisfy the relation

    Mw/Mn≧7.5×log (MFR)-1.2;

a weight ratio ( A-1!: B-1!) between said ethylene/α-olefin copolymerA-1! and said high-pressure radical polymerization low-densitypolyethylene B-1! being in the range of 99:1 to 60:40.

The second ethylene copolymer composition according the presentinvention is an ethylene copolymer composition comprising:

A-1! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms in an amount of 60 to 99% by weight, said copolymerhaving such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT>2.2×MFR.sup.-0.84,

(v) the flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation

    FI>75×MFR,

and

(vi) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,

in the case of MFR<10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-2! at least one crystalline polyolefin in an amount of 1 to 40% byweight, said crystalline polyolefin being selected from the groupconsisting of:

(B-I) an ethylene homopolymer or a copolymer of ethylene with anα-olefin of 3 to 20 carbon atoms, prepared by using non-metallocene typecatalyst, having a melt flow rate (MFR) of 0.01 to 100 g/10 min at 190°C. under a load of 2.16 kg and a density of not less than 0.900 g/cm³,

(B-II) a propylene homopolymer or a copolymer of propylene with at leastone olefin selected from ethylene and an α-olefin of 4 to 20 carbonatoms, having a melt flow rate (MFR) of 0.1 to 100 g/10 min at 230° C.under a load of 2.16 kg and a density of not less than 0.900 g/cm³, and

(B-III) a homopolymer of an α-olefin of 4 to 20 carbon atoms or acopolymer of α-olefins of 4 to 20 carbon atoms, having a melt flow rate(MFR) of 0.1 to 100 g/10 min at 230° C. under a load of 2.16 kg and adensity of not less than 0.900 g/cm³.

The third ethylene copolymer composition according the present inventionis an ethylene copolymer composition comprising:

A-1! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms in an amount of 60 to 99% by weight, said copolymerhaving such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT>2.2×MFR.sup.-0.84,

(v) the flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation

    FI>75×MFR,

and

(vi) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-3! an olefin type elastomer in an amount of 1 to 40% by weight, saidelastomer having such properties that

(i) the density (d) is not more than 0.900 g/cm³, and

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 100 g/10 min; a density ratio ( B-3!/ A-1!) of thedensity of said olefin type elastomer B-3! to the density of saidethylene/α-olefin copolymer A-1! being less than 1.

The fourth ethylene copolymer composition according the presentinvention is an ethylene copolymer composition comprising:

Ia! an ethylene/α-olefin copolymer composition which comprises A-2! anethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to 20carbon atoms in an amount of 5 to 95% by weight and A-3! anethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to 20carbon atoms in an amount of 5 to 95% by weight,

said ethylene/α-olefin copolymer A-2! having such properties that

(i) the density (d) is in the range of 0.880 to 0.940 g/cm³,

(ii) the intrinsic viscosity η_(A-2) ! as measured in decalin at 135° C.is in the range of 1.0 to 10.0 dl/g,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT>2.2×MFR.sup.-0.84,

(v) the flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation

    FI>75×MFR,

and

(vi) the amount (W (% by weight)) of a decane-soluble portion at roomtemperature and the density (d) satisfy the relation

    W<80×exp (-100(d-0.88))+0.1,

said ethylene/α-olefin copolymer A-3! having such properties that

(i) the density (d) is in the range of 0.910 to 0.960 g/cm³,

(ii) the intrinsic viscosity η_(A-3) ! as measured in decalin at 135° C.is in the range of 0.5 to 2.0 dl/g,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

and

(iv) the amount (W (% by weight)) of a decane-soluble portion at roomtemperature and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1,

said ethylene/α-olefin copolymer composition Ia! having such propertiesthat

(i) the density ratio ( A-2!/ A-3!) of the density of saidethylene/α-olefin copolymer A-2! to the density of saidethylene/α-olefin copolymer A-3! is less than 1,

(ii) the intrinsic viscosity ratio ( η_(A-2) !/ η_(A-3) !) of theintrinsic viscosity of said ethylene/α-olefin copolymer A-2! to theintrinsic viscosity of said ethylene/α-olefin copolymer A-3! is not lessthan 1,

(iii) the density of said composition is in the range of 0.890 to 0.955g/cm³, and

(iv) the melt flow rate (MFR) of said composition at 190° C. under aload of 2.16 kg is in the range of of 0.1 to 100 g/10 min; and

II-a! B-1! a high-pressure radical polymerization low-densitypolyethylene having such properties that

(i) the melt flow rate (MFR) is in the range of 0.1 to 50 g/10 min, and

(ii) the molecular weight distribution (Mw/Mn, Mw=weight-averagemolecular weight, Mn=number-average molecular weight) measured by GPCand the melt flow rate (MFR) satisfy the relation

    Mw/Mn≧7.5×log (MFR)-1.2;

a weight ratio ( Ia!: IIa!) between said ethylene/α-olefin copolymercomposition Ia! and said high-pressure radical polymerizationlow-density polyethylene IIa! being in the range of 99:1 to 60:40.

The first to fourth ethylene copolymer compositions according to thepresent invention are excellent in heat stability, melt tension andflowability under the high-shear region, and films formed from thesecompositions are excellent in transparency, mechanical strength andblocking resistance.

The fifth ethylene copolymer composition according to the presentinvention is an ethylene copolymer composition comprising:

A-4! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms having such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT≦2.2×MFR.sup.-0.84,

and

(v) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-4! a high-pressure radical polymerization low-density polyethylenehaving such properties that

(i) the melt flow rate (MFR) is in the range of 0.1 to 50 g/10 min, and

(ii) the molecular weight distribution (Mw/Mn, Mw=weight-averagemolecular weight, Mn=number-average molecular weight) measured by GPCand the melt flow rate (MFR) satisfy the relation

    7.5×log (MFR)-1.2≦Mw/Mn≦7.5×log (MFR)+12.5;

a weight ratio ( A-4!: B-4!) between said ethylene/α-olefin copolymerA-4! and said high-pressure radical polymerization low-densitypolyethylene B-4! being in the range of 99:1 to 60:40.

The sixth ethylene copolymer composition according to the presentinvention is an ethylene copolymer composition comprising:

A-4! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms in an amount of 60 to 99% by weight, said copolymerhaving such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT≦2.2×MFR.sup.-0.84,

and

(v) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-2! at least one crystalline polyolefin in an amount of 1 to 40% byweight, said crystalline polyolefin being selected from the groupconsisting of:

(B-I) an ethylene homopolymer or a copolymer of ethylene with anα-olefin of 3 to 20 carbon atoms, prepared by using non-metallocene typecatalyst, having a melt flow rate (MFR) of 0.01 to 100 g/10 min at 190°C. under a load of 2.16 kg and a density of not less than 0.900 g/cm³,

(B-II) a propylene homopolymer or a copolymer of propylene with at leastone olefin selected from ethylene and an α-olefin of 4 to 20 carbonatoms, having a melt flow rate (MFR) of 0.1 to 100 g/10 min at 230° C.under a load of 2.16 kg and a density of not less than 0.900 g/cm³, and

(B-III) a homopolymer of an α-olefin of 4 to 20 carbon atoms or acopolymer of α-olefins of 4 to 20 carbon atoms, having a melt flow rate(MFR) of 0.1 to 100 g/10 min at 230° C. under a load of 2.16 kg and adensity of not less than 0.900 g/cm³.

The seventh ethylene copolymer composition according the presentinvention is an ethylene copolymer composition comprising:

A-4! an ethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to20 carbon atoms in an amount of 60 to 99% by weight, said copolymerhaving such properties that

(i) the density (d) is in the range of 0.880 to 0.960 g/cm³,

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 200 g/10 min,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT≦2.2×MFR.sup.-0.84,

and

(v) the amount (W (% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and

B-3! an olefin type elastomer in an amount of 1 to 40% by weight, saidelastomer having such properties that

(i) the density (d) is not more than 0.900 g/cm³, and

(ii) the melt flow rate (MFR) at 190° C. under a load of 2.16 kg is inthe range of 0.01 to 100 g/10 min; a density ratio ( B-3!/ A-4!) of thedensity of said olefin type elastomer B-3! to the density of saidethylene/α-olefin copolymer A-4! being less than 1.

The eighth ethylene copolymer composition according the presentinvention is an ethylene copolymer composition comprising:

Ib! an ethylene/α-olefin copolymer composition which comprises A-5! anethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to 20carbon atoms in an amount of 5 to 95% by weight and A-6! anethylene/α-olefin copolymer of ethylene with an α-olefin of 3 to 20carbon atoms in an amount of 5 to 95% by weight,

said ethylene/α-olefin copolymer A-5! having such properties that

(i) the density (d) is in the range of 0.880 to 0.940 g/cm³,

(ii) the intrinsic viscosity η_(A-5) ! as measured in decalin at 135° C.is in the range of 1.0 to 10.0 dl/g,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT≦2.2×MFR.sup.-0.84,

and

(v) the amount (W (% by weight)) of a decane-soluble portion at roomtemperature and the density (d) satisfy the relation

    W<80×exp (-100(d-0.88))+0.1,

said ethylene/α-olefin copolymer A-6! having such properties that

(i) the density (d) is in the range of 0.910 to 0.960 g/cm³,

(ii) the intrinsic viscosity η_(A-6) ! as measured in decalin at 135° C.is in the range of 0.5 to 2.0 dl/g,

(iii) the temperature (Tm (°C.)) at which the endothermic curve of saidcopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

and

(iv) the amount (W (% by weight)) of a decane-soluble portion at roomtemperature and the density (d) satisfy the relation,

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1,

said ethylene/α-olefin copolymer composition Ib! having such propertiesthat

(i) the density ratio ( A-5!/ A-6!) of the density of saidethylene/α-olefin copolymer A-5! to the density of saidethylene/α-olefin copolymer A-6! is less than 1,

(ii) the intrinsic viscosity ratio ( η_(A-5) !/ η_(A-6) !) of theintrinsic viscosity of said ethylene/α-olefin copolymer A-5! to theintrinsic viscosity of said ethylene/α-olefin copolymer A-6! is not lessthan 1,

(iii) the density of said composition is in the range of 0.890 to 0.955g/cm³, and

(iv) the melt flow rate (MFR) of said composition at 190° C. under aload of 2.16 kg is in the range of 0.1 to 50 g/10 min; and

IIb! B-4! a high-pressure radical polymerization low-densitypolyethylene having such properties that

(i) the melt flow rate (MFR) is in the range of 0.1 to 50 g/10 min, and

(ii) the molecular weight distribution (Mw/Mn, Mw=weight-averagemolecular weight, Mn=number-average molecular weight) measured by GPCand the melt flow rate (MFR) satisfy the relation

    7.5×log (MFR)-1.2≦Mw/Mn≦7.5×log (MFR)+12.5;

a weight ratio ( Ib!: IIb!) between said ethylene/α-olefin copolymercomposition Ib! and said high-pressure radical polymerizationlow-density polyethylene IIb! being in the range of 99:1 to 60:40.

The fifth to eighth ethylene copolymer compositions according to thepresent invention are excellent in heat stability and melt tension, andfilms obtained from these compositions are excellent in transparency,mechanical strength and blocking resistance.

DETAILED DESCRIPTION OF THE INVENTION

The first to eighth ethylene copolymer compositions according to thepresent invention are described in detail hereinafter.

In this specification, the term "polymerization" is used to mean notonly homopolymerization but also copolymerization, and the term"polymer" is used to mean not only a homopolymer but also a copolymer.

First ethylene copolymer composition

The first ethylene copolymer composition according to the presentinvention is formed from an ethylene/α-olefin copolymer A-1! and ahigh-pressure radical polymerization low-density polyethylene B-1!.

Ethylene/α-olefin copolymer A-1!

The ethylene/α-olefin copolymer A-1! used in the invention is a randomcopolymer of ethylene with an α-olefin of 3 to 20 carbon atoms. Examplesof the α-olefin of 3 to 20 carbon atoms employable for copolymerizationwith ethylene include propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene.

In the ethylene/α-olefin copolymer A-1!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, and constituent units derived from an α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

In the invention, the composition of an ethylene/α-olefin copolymer isdetermined by ¹³ C-NMR spectrum analysis of a sample prepared byuniformly dissolving about 200 mg of the copolymer in 1 ml ofhexachlorobutadiene in a sample tube usually having a diameter of 10mm.o slashed. under the conditions of a measuring temperature of 120°C., a measuring frequency of 25.05 MHz, a spectrum width of 1,500 Hz, apulse repetition period of 4.2 sec and a pulse width of 6 μsec.

The ethylene/α-olefin copolymer A-1! used in the invention has thefollowing properties (i) to (vi).

(i) The density (d) is usually in the range of 0.880 to 0.960 g/cm³,preferably 0.890 to 0.935 g/cm³, more preferably 0.905 to 0.930 g/cm³.

In the invention, the density (d) of an ethylene/α-olefin copolymer isdetermined by means of a density gradient tube using a strand, which hasbeen obtained at the time of a melt flow rate (MFR) measurementdescribed below and which is treated by heating at 120° C. for 1 hourand slowly cooling to room temperature over 1 hour.

(ii) The melt flow rate (MFR) is usually in the range of 0.01 to 200g/10 min, preferably 0.05 to 50 g/10 min, more preferably 0.1 to 10 g/10min.

In the invention, the melt flow rate (MFR) of an ethylene/α-olefincopolymer is determined in accordance with ASTM D1238-65T under theconditions of a temperature of 190° C. and a load of 2.16 kg.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

In the invention, the temperature (Tm (°C.)) at which the endothermiccurve of an ethylene/α-olefin copolymer measured by a differentialscanning calorimeter (DSC) shows the maximum peak is sought from anendothermic curve obtained by filling about 5 mg of a sample in analuminum pan, heating to 200° C. at a rate of 10° C./min, holding thesample at 200° C. for 5 minutes, lowering the temperature to roomtemperature at a rate of 20° C./min, and then heating at a rate of 10°C./min. This measurement is carried out using a DSC-7 type apparatusproduced by Perkin Elmer Co.

(iv) The melt tension (MT (g)) and the melt flow rate (MFR) satisfy therelation:

    MT>2.2×MFR.sup.-0.84.

The ethylene/α-olefin copolymer A-1! employable for the invention isexcellent in melt tension (MT) and has good moldability.

In the invention, the melt tension (MT (g)) of an ethylene/α-olefincopolymer is determined by measuring a stress given when a moltencopolymer was stretched at a constant rate. That is, a powdery polymerwas melted in a conventional manner, and the molten polymer waspelletized to give a measuring sample. Then, the MT of the sample wasmeasured under the conditions of a resin temperature of 190° C., anextrusion rate of 15 mm/min and a take-up rate of 10 to 20 m/min using aMT measuring apparatus (produced by Toyo Seiki Seisakusho K.K.) having anozzle diameter of 2.09 mm.o slashed. and a nozzle length of 8 mm.During the pelletization, to the ethylene/α-olefin copolymer A-1! wereadded tri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant inan amount of 0.05% by weight,n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate as a heatstabilizer in an amount of 0.1% by weight and calcium stearate as ahydrochloric acid absorbent in an amount of 0.05% by weight.

(v) The flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of a molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation:

    FI>75×MFR,

    preferably FI>100×MFR,

    more preferably FI>120×MFR.

The ethylene/α-olefin copolymer A-1! whose FI and MFR satisfy theabove-mentioned relation shows a small processing torque because a lowstress can be kept even at a high-shear rate, and has good moldability.

In the invention, the flow index (FI) of an ethylene/α-olefin copolymeris defined by a shear rate which is given when a shear stress reaches2.4×10⁶ dyne/cm² at 190° C. The flow index (FI) is determined byextruding a resin from a capillary while changing a shear rate andmeasuring the shear rate given when the shear stress reaches theabove-mentioned value. In this measurement, the same sample as describedin the above-mentioned MT measurement is used, and the FI is measuredunder the conditions of a resin temperature of 190° C. and a shearstress of about 5×10⁴ to 3×10⁶ dyne/cm² using a capillary type flowproperty tester produced by Toyo Seiki Seisakusho K.K.

In the measurement, a diameter of the nozzle (capillary) is changed asfollows depending on the MFR (g/10 min) of the resin to be measured:

in the case of MFR>20: 0.5 mm

in the case of 20≧MFR>3: 1.0 mm

in the case of 3≧MFR>0.8: 2.0 mm, and

in the case of 0.8≧MFR: 3.0 mm.

(vi) The quantity fraction (W (% by weight)) of a n-decane-solublecomponent at 23° C. and the density (d) satisfy the relation:

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1,

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1.

In the invention, the measurement of the n-decane-soluble componentquantity of an ethylene/α-olefin copolymer (polymer having a smallersoluble component quantity has a narrower composition distribution) iscarried out by adding about 3 g of the copolymer to 450 ml of n-decane,dissolving the copolymer at 145° C., cooling the resulting solution to23° C., removing a n-decane-insoluble portion by filtering, andrecovering a n-decane-soluble portion from the filtrate.

It may be concluded that the ethylene/α-olefin copolymer A-1! whichsatisfies the above mentioned relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the quantity fraction (W) of a n-decane-solublecomponent and the density (d), has a narrow composition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-1! desirably is not more than 0.5 per1,000 carbon atoms and less than 1 per one molecule of the copolymer.

In the invention, the number of unsaturated bond of an ethylene/α-olefincopolymer is determined by means of ¹³ C-NMR, that is, an area intensityof signals assigned to bond other than double bond, i.e., signals withinthe range of 10 to 50 ppm, and an area intensity of signals assigned todouble bond, i.e., signals within the range of 105 to 150 ppm, aresought from the integral curve, and the number of the unsaturated bondis determined as a ratio thereof.

The ethylene/α-olefin copolymer A-1! having the properties as mentionedabove can be prepared by copolymerizing ethylene with an α-olefin of 3to 20 carbon atoms in the presence of an olefin polymerization catalyst(1) or a prepolymerization catalyst (1) formed from (a-1) a transitionmetal compound catalyst component, (b) an organoaluminum oxy-compoundcatalyst component, (c) a carrier, and if necessary, (d) anorganoaluminum compound catalyst component, all components beingdescribed later, in such a manner that the resulting copolymer wouldhave a density of 0.880 to 0.960 g/cm³.

First, the transition metal compound catalyst component (a-1) isexplained below.

The transition metal compound catalyst component (a-1) (sometimesreferred to as "component (a-1)" hereinafter) is a compound of atransition metal in Group IVB of the periodic table which has abidentate ligand formed by bonding two groups selected from specificindenyl or substituted indenyl groups through a lower alkylene group, ora compound of a transition metal in Group IVB of the periodic tablewhich has as a ligand a cyclopentadienyl group having 2-5 substituentgroups selected from methyl groups and ethyl groups. Concretely, thecomponent (a-1) is a transition metal compound represented by thefollowing formula I! or II!.

    MKL.sup.1.sub.X-2                                           I!

In the formula I!, M is a transition metal atom selected from Group IVBof the periodic table, K and L¹ are each a ligand coordinating to thetransition metal atom. The ligand K is a bidentate ligand formed bybonding the same or different indenyl groups, substituted indenyl groupsor their partially hydrogenated products through a lower alkylene group,and the ligand L¹ is a hydrocarbon group of 1 to 12 carbon atoms, analkoxy group, an aryloxy group, a halogen atom, a trialkylsilyl group ora hydrogen atom. X is a valance of the transition metal atom M.

    ML.sup.2.sub.X                                              II!

In the formula II!, M is a transition metal atom selected from Group IVBof the periodic table, L² is a ligand coordinating to the transitionmetal atom, at least two of L² are substituted cyclopentadienyl groupshaving 2-5 substituent groups selected from methyl group and ethylgroup, and L² other than the substituted cyclopentadienyl group is ahydrocarbon group of 1 to 12 carbon atoms, an alkoxy group, an aryloxygroup, a halogen atom, a trialkylsilyl group or a hydrogen atom. X is avalance of the transition metal atom M.

In the above formula I!, M is a transition metal atom selected fromGroup IVB of the periodic table, and it is concretely zirconium,titanium or hafnium, preferably zirconium.

K is a ligand coordinating to the transition metal atom, and is abidentate ligand formed by bonding the same or different indenyl groups,substituted indenyl groups or partially hydrogenated products of theindenyl or substituted indenyl groups through a lower alkylene group.

Concrete examples thereof include ethylenebisindenyl group,ethylenebis(4,5,6,7-tetrahydro-1-indenyl) group,ethylenebis(4-methyl-1-indenyl) group, ethylenebis(5-methyl-1-indenyl)group, ethylenebis(6-methyl-1-indenyl) group andethylenebis(7-methyl-1-indenyl) group.

L¹ is a hydrocarbon group of 1 to 12 carbon atoms, an alkoxy group, anaryloxy group, a halogen atom, a trialkylsilyl group or a hydrogen atom.

Examples of the hydrocarbon group of 1 to 12 carbon atoms include alkylgroup, cycloalkyl group, aryl group and aralkyl group. Concrete examplesthereof include alkyl group such as methyl group, ethyl group, n-propylgroup, isopropyl group, n-butyl group, isobutyl group, sec-butyl group,t-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexylgroup and decyl group; cycloalkyl group such as cyclopentyl group andcyclohexyl group; aryl group such as phenyl group and tolyl group; andaralkyl group such as benzyl group and neophyl group.

Examples of the alkoxy group include methoxy group, ethoxy group,n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group,sec-butoxy group, t-butoxy group, pentoxy group, hexoxy group and octoxygroup.

Examples of the aryloxy group include phenoxy group and the like.

Examples of the halogen atom include fluorine, chlorine, bromine andiodine.

Examples of the trialkylsilyl group include trimethylsilyl group,triethylsilyl group and triphenylsilyl group.

Listed below are examples of the transition metal compound representedby the formula I!.

Ethylenebis(indenyl) zirconium dichloride,

Ethylenebis(4-methyl-1-indenyl)zirconium dichloride,

Ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride,

Ethylenebis(5-methyl-1-indenyl)zirconium dichloride,

Ethylenebis(6-methyl-1-indenyl)zirconium dichloride,

Ethylenebis(7-methyl-1-indenyl)zirconium dichloride,

Ethylenebis(4-methyl-1-indenyl)zirconium dibromide,

Ethylenebis(4-methyl-1-indenyl)zirconium methoxychloride,

Ethylenebis(4-methyl-1-indenyl)zirconium ethoxychloride,

Ethylenebis(4-methyl-1-indenyl)zirconium butoxychloride,

Ethylenebis(4-methyl-1-indenyl)zirconium dimethoxide,

Ethylenebis(4-methyl-1-indenyl)zirconium methylchloride

Ethylenebis(4-methyl-1-indenyl)dimethylzirconium,

Ethylenebis(4-methyl-1-indenyl)zirconium benzylchloride,

Ethylenebis(4-methyl-1-indenyl)dibenzylzirconium,

Ethylenebis(4-methyl-1-indenyl)zirconium phenylchloride, and

Ethylenebis(4-methyl-1-indenyl)zirconium hydride chloride.

Also employable in the invention are transition metal compounds obtainedby substituting titanium metal or hafnium metal for the zirconium metalin the above-exemplified zirconium compounds.

Of the above-exemplified transition metal compounds represented by theformula I!, particularly preferred are ethylenebis(indenyl)zirconiumdichloride, ethylenebis(4-methyl-1-indenyl)zirconium dichloride andethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride.

In the above-mentioned formula II!, M is a transition metal selectedfrom Group IVB of the periodic table, and concrete preferable examplesof M include zirconium, titanium and hafnium. Of these, particularlypreferred is zirconium.

L² is a ligand coordinated to the transition metal, and at least two ofthem are substituted cyclopentadienyl groups having 2-5 of substituentsselected from methyl group and ethyl group. Each of ligand may be thesame or different. The substituted cyclopentadienyl groups are thesubstituted cyclopentadienyl groups having 2 or more of substituents,preferably the substituted cyclopentadienyl groups having 2 or 3 ofsubstituents, more preferably the substituted cyclopentadienyl groupshaving two substituents, particularly the 1,3-substitutedcyclopentadienyl groups. Each of substituent may be the same ordifferent.

In the above-mentioned formula II!, ligand L² other than the substitutedcyclopentadienyl group is a hydrocarbon group of 1 to 12 carbon atoms,an alkoxy group, an aryloxy group, halogen, trialkylsilyl group orhydrogen as similar to the ligand L¹ in the above-mentioned formula Thetransition metal compound represented by the general formula II!include, for example,

Bis(dimethylcyclopentadienyl)zirconium dichloride,

Bis(diethylcyclopentadienyl)zirconium dichloride,

Bis(methylethylcyclopentadienyl)zirconium dichloride,

Bis(dimethylethylcyclopentatienyl)zirconium dichloride,

Bis(dimethylcyclopentadienyl)zirconium dibromide,

Bis(dimethylcyclopentadienyl)zirconium methoxychloride,

Bis(dimethylcyclopentadienyl)zirconium ethoxychloride,

Bis(dimethylcyclopentadienyl)zirconium butoxychloride,

Bis(dimethylcyclopentadienyl)zirconium diethoxide,

Bis(dimethylcyclopentadienyl)zirconium methylchloride,

Bis(dimethylcyclopentadienyl)zirconium dimethyl,

Bis(dimethylcyclopentadienyl)zirconium benzylchloride,

Bis(dimethylcyclopentadienyl)zirconium dibenzyl,

Bis(dimethylcyclopentadienyl)zirconium phenylchloride, andBis(dimethylcyclopentadienyl)zirconium hydridechloride.

In the above exemplified compounds, di-substituted cyclopentadienylinclude 1,2- and 1,3-substituted, and tri-substituted include 1,2,3- and1,2,4-substituted.

There may also be used transition metal compounds obtained bysubstituting titanium or hafnium for zirconium in the above-exemplifiedzirconium compounds.

In the above-mentioned transition metal compounds represented by thegeneral formula II!, particularly preferred is

Bis(1,3-dimethylcyclopentadienyl)zirconium dichloride,

Bis(1,3-diethylcyclopentadienyl)zirconium dichloride, or

Bis(1-methyl-3-ethylcyclopentadienyl)zirconium dichloride.

Next, the organoaluminum oxy-compound (b) hereinafter sometimes referredto as component (b)! is explained below.

The organoaluminum oxy-compound (b) may be a known benzene-solublealuminoxane or the benzene-insoluble organoaluminum oxy-compound havingbeen disclosed in Japanese Patent L-O-P No. 276807/1990.

The above-mentioned aluminoxane may be prepared, for example, by thefollowing procedures:

(1) a procedure for recovering an aluminoxane as its hydrocarbonsolution which comprises adding an organoaluminum compound such astrialkylaluminum to a suspension in a hydrocarbon medium of a compoundcontaining adsorbed water, or a salt containing water of crystallizationsuch as magnesium chloride hydrate, copper sulfate hydrate, aluminumsulfate hydrate, nickel sulfate hydrate and cerium chloride hydrate, andreacting the organoaluminum compound; and

(2) a procedure for recovering an aluminoxane as its hydrocarbonsolution which comprises reacting water, ice or steam directly with anorganoaluminum compound such as trialkylaluminum in a solvent such asbenzene, toluene, ethyl ether and tetrahydrofuran.

(3) a procedure for recovering an aluminoxane which comprises reactingan organotinoxide such as dimethyltinoxide and dibutyltinoxide with anorganoaluminum compound such as trialkylaluminum in a solvent such asdecane, benzene or toluene.

Moreover, the aluminoxane may contain a small amount of an organometalcomponent. Furthermore, the solvent or unreacted organoaluminum compoundmay be removed from the above-mentioned recovered aluminoxane-containingsolution, by distillation, and the aluminoxane may be redissolved in asolvent.

Concrete examples of the organoaluminum compound used for thepreparation of the aluminoxane include

trialkylaluminum such as trimethylaluminum, triethylaluminum,tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum,tripentylaluminum, trihexylaluminum, trioctylaluminum andtridecylaluminum;

tricycloalkylaluminums such as tricyclohexylaluminum andtricyclooctylaluminum;

dialkylaluminum halides such as dimethylaluminum chloride,diethylaluminum chloride, diethylaluminum bromide and diisobutylalumunumchloride;

dialkylaluminum hydrides such as diethylaluminum hydride anddiisobutylaluminum hydride;

dialkylaluminum alkoxides such as dimethylaluminum methoxide anddiethylaluminum ethoxide; and

dialkylaluminum aryloxides such as diethylaluminum phenoxide.

Of these compounds, trialkylaluminum is particularly preferable.

Furthermore, there may also be used as the organoaluminum compoundisoprenylaluminum represented by the general formula

    (i-C.sub.4 H.sub.9).sub.x Al.sub.y (C.sub.5 H.sub.10).sub.z

wherein x, y and z are each a positive number, and z≧2x.

The organoaluminum compounds mentioned above may be used either singlyor in combination.

Solvents used for the solutions of the aluminoxane include aromatichydrocarbons such as benzene, toluene, xylene, cumene and cymene;aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane,dodecane, hexadecane and octadecane; alicyclic hydrocarbons such ascyclopentane, cyclohexane, cyclooctane and methylcyclopentane; petroleumfractions such as gasoline, kerosene and gas oil; and halogenatedcompounds derived from the above-mentioned aromatic hydrocarbons,aliphatic hydrocarbons and alicyclic hydrocarbons, especiallychlorinated and brominated hydrocarbons.

In addition, there may also be used ethers such as ethyl ether andtetrahydrofuran. Of these solvents as exemplified above, aromatichydrocarbons are particularly preferred.

The benzene-insoluble organoaluminum oxy-compounds used as component (b)contain an Al component soluble in benzene at 60° C. in an amount of notgreater than 10%, preferably not greater than 5%, particularlypreferably not greater than 2% in terms of Al atom, and they areinsoluble or sparingly soluble in benzene.

Solubility in benzene of such organoaluminum oxy-compounds as mentionedabove is obtained by suspending in 100 ml of benzene the organoaluminumoxy-compound in an amount corresponding to 100 mg atoms in terms of Al,mixing the resulting suspension at 60° C. for 6 hours with stirring,filtering the resulting mixture with a G-5 glass filter equipped with ajacket kept at 60° C., washing 4 times the solid portion separated onthe filter with 50 ml of benzene at 60° C., and measuring the amount (xmmole) of Al atoms present in the whole filtrate.

Next, the carrier (c) is explained below. The carrier (c) hereinaftersometimes referred to as component (c)! is a solid inorganic or organiccompound in granules or fine particles having a particle size of 10 to300 μm, preferably 20 to 200 μm. Of these carriers, porous oxides arepreferable as inorganic carriers. Concrete examples of the oxidecarriers include SiO₂, Al₂ O₃, MgO, ZrO₂, TiO₂, B₂ O₃, CaO, ZnO, BaO,ThO₂, or a mixture of these compounds such as SiO₂ --MgO, SiO₂ --Al₂ O₃,SiO₂ --TiO₂, SiO₂ --V₂ O₅, SiO₂ --Cr₂ O₃ and SiO₂ --TiO₂ --MgO. Of thesecarriers, preferred are those comprising at least one compound selectedfrom the group consisting of SiO₂ and Al₂ O₃ as a major component.

Furthermore, the above-mentioned inorganic oxide or oxides may alsocontain a small amount of a carbonate, a sulfate, a nitrate and an oxidesuch as Na₂ CO₃, K₂ CO₃, CaCO₃, MgCO₃, Na₂ SO₄, Al₂ (SO₄)₃, BaSO₄, KNO₃,Mg(NO₃)₂, Al(NO₃)₃, Na₂ O, K₂ O and LiO₂.

Though the porous inorganic carriers have different properties amongthem depending on the types and preparation methods thereof, thecarriers preferably used in the invention have a specific surface areaof 50 to 1000 m² /g, preferably 100 to 700 m² /g, a pore volume ofdesirably 0.3 to 2.5 cm² /g. The carriers are prepared if necessary byfiring at a temperature of 100° C. to 1000° C., preferably 150° C. to700° C.

Moreover, there can be mentioned organic compounds in solid granules orfine solid particles each having a particle size of 10 to 300 μm ascarriers which can be used as the component (c). Examples of theseorganic compounds include (co)polymers containing as the main componentconstituent units derived from an α-olefin of 2 to 14 carbon atoms, suchas ethylene, propylene, 1-butene and 4-methyl-1-pentene, or polymers orcopolymers containing as the main component constituent units derivedfrom vinylcyclohexane or styrene.

Next, the optionally used organoaluminum compound catalyst component (d)is explained below.

Examples of the organoaluminum compound (d) hereinafter sometimesreferred to as component (d)! include an organoaluminum compoundrepresented by the following formula III!.

    R.sup.1.sub.n AlX.sub.3-n                                   III!

wherein R¹ is a hydrocarbon group of 1 to 12 carbon atoms, X is halogenor hydrogen, and n is 1 to 3.

In the above formula III!, R¹ is a hydrocarbon group of 1 to 12 carbonatoms, for example, an alkyl group, a cycloalkyl group or an aryl group.Concrete examples of R¹ include methyl, ethyl, n-propyl, isopropyl,isobutyl, pentyl, hexyl, octyl, cyclopentyl, cyclohexyl, phenyl andtolyl.

Concrete examples of such organoaluminum compounds (d) include

trialkylaluminum such as trimethylaluminum, triethylaluminum,triisopropylaluminum, triisobutylaluminum, trioctylaluminum andtri-2-ethylhexylaluminum;

alkenylaluminum such as isoprenylaluminum;

dialkylaluminum halides such as dimethylaluminum chloride,diethylaluminum chloride, diisopropylaluminum chloride,diisobutylaluminum chloride and dimethylaluminum bromide;

alkylaluminum sesquihalides such as methylaluminum sesquichloride,ethylaluminum sesquichloride, isopropylaluminum sesquichloride,butylaluminum sesquichloride and ethylaluminum sesquibromide;

alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminumdichloride, isopropylaluminum dichloride and ethylaluminum dibromide;and

alkylaluminum hydrides such as diethylaluminum hydride anddiisobutylaluminum hydride.

Furthermore, there may also be used other organoaluminum compoundsrepresented by the following formula IV! as the organoaluminum compoundcatalyst component (d);

    R.sup.1.sub.n AlY.sub.3-n                                   IV!

wherein R¹ is as defined previously, Y is --OR², --OSiR³ ₃, --OAlR⁴ ₂,--NR⁵ ₂, --SiR⁶ ₃ or --N(R⁷)AlR⁸ ₂, n is 1 to 2, R², R³, R⁴ and R⁸ areeach methyl, ethyl, isopropyl, isobutyl, cyclohexyl or phenyl, R⁵ ishydrogen, methyl, ethyl, isopropyl, phenyl or trimethylsilyl, R⁶ and R⁷are each methyl or ethyl.

The organoaluminum compounds as mentioned above include, in concrete,such compounds as enumerated below.

(1) Compounds of the formula R¹ _(n) Al(OR²)_(3-n) such asdimethylaluminum methoxide, diethylaluminum ethoxide anddiisobutylaluminum methoxide.

(2) Compounds of the formula R¹ _(n) Al(OSiR³ ₃)_(3-n) such as Et₂Al(OSiMe₃), (iso-Bu)₂ Al (OSiMe₃) and (iso-Bu)₂ Al(OSiEt₃).

(3) Compounds of the formula R¹ _(n) Al(OAlR⁴ ₂)_(3-n) such as Et₂AlOAlEt₂ and (iso-Bu)₂ AlOAl (iso-Bu)₂.

(4) Compounds of the formula R¹ _(n) Al(NR⁵ ₂)_(3-n) such as Me₂ AlNEt₂,Et₂ AlNHMe, Me₂ AlNHEt, Et₂ AlN(SiMe₃)₂, (iso-Bu)₂ AlN(SiMe₃)₂.

(5) Compounds of the formula R¹ _(n) Al(SiR⁶ ₃)_(3-n) such as (iso-Bu)₂AlSiMe₃.

(6) Compounds of the formula ##STR1## such as ##STR2##

Of the organoaluminum compounds as exemplified above, preferred arethose having the formulas

    R.sup.1.sub.3 Al, R.sup.1.sub.n Al(OR.sup.2).sub.3-n and R.sup.1.sub.n Al(OAlR.sup.4.sub.2).sub.3-n,

and particularly preferred are those having the above-mentioned formulasin which R¹ is isoalkyl and n is 2.

The ethylene/α-olefin copolymer A-1! used in the present invention canbe prepared by the olefin polymerization catalyst (1) formed bycontacting the above-mentioned components (a-1), (b), (c) and ifnecessary, component (d). Though the mixing of these components (a-1),(b), (c) and (d) may be conducted in arbitrarily selected order, themixing and contacting is preferably conducted in the order of:

mixing and contacting the components (b) and (c), followed by mixing andcontacting the component (a-1), and if necessary, mixing and contactingthe component (d).

The mixing of the above-mentioned components (a-1), (b), (c) and (d) canbe carried out in an inert hydrocarbon.

As the inert hydrocarbon solvent for preparing the catalyst, there maybe mentioned an aliphatic hydrocarbon, such as propane, butane, pentane,hexane, heptane, octane, decane, dodecane and kerosene;

an alicyclic hydrocarbon, such as cyclopentane, cyclohexane andmethylcyclopentane;

an aromatic hydrocarbon, such as benzene, toluene and xylene;

a halogenated hydrocarbon, such as ethylene chloride, chlorobenzene anddichloromethane; and a mixture thereof.

In contacting and mixing of the components (a-1), (b), (c) and ifnecessary, component (d), the component (a-1) is used usually in anamount of 5×10⁻⁶ to 5×10⁻⁴ mol, preferably 1×10⁻⁵ to 2×10⁻⁴ mol based on1 g of the component (c), and the concentration thereof is 1×10⁻⁴ to2×10⁻² mol/l, preferably 2×10⁻⁴ to 1×10⁻² mol/l. The atomic ratio(Al/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-1) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5.

The components (a-1), (b) and (c), and if necessary, the component (d)are mixed and contacted at a temperature of usually -50° to 150° C.,Preferably -20° to 120° C., with a contact time of 1 minute to 50 hours,preferably 10 minutes to 25 hours.

In the catalyst (1) for olefin polymerization obtained as describedabove, it is desirable that the transition metal derived from component(a-1) is supported in an amount of 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably1×10⁻⁵ to 2×10⁻⁴ g atom, and aluminum derived from components (b) and(d) is supported in an amount of 10⁻³ to 5×10⁻² g atom, preferably2×10⁻³ to 2×10⁻² g atom, all the amounts being based on 1 g of thecomponent (c).

Further, the catalyst for preparing the ethylene/α-olefin copolymer A-1!used in the present invention may be a prepolymerized catalyst (1)obtained by prepolymerization of olefin in the presence of theabove-mentioned components (a-1), (b) and (c), and if necessary, (d).

The prepolymerized catalyst (1) can be prepared by mixing the component(a-1), the component (b), the component (c), and if necessary, thecomponent (d), introducing olefin to the resulting mixture in the inerthydrocarbon solvent, and carrying out prepolymerization.

The olefins which can be prepolymerized include ethylene and α-olefinseach having 3 to 20 carbon atoms, for example, propylene, 1-butene,1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodeceneand 1-tetradecene. Of these, particularly preferred is ethylene or thecombination of ethylene and α-olefin used in the polymerization.

During the prepolymerization, the component (a-1) is used usually in aconcentration of is 1×10⁻⁶ to 2×10⁻² mol/l, preferably 5×10⁻⁵ to 1×10⁻²mol/l and amount thereof is usually 5×10⁻⁶ to 5×10⁻⁴ mol, preferably1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g of the component (c).

The atomic ratio (Al/transition metal) of the aluminum in the component(b) to the transition metal in the component (a-1) is usually 10 to 500,preferably 20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms(Al-d) in the component (d) optionally used to the aluminum atoms (Al-b)in the component (b) is usually 0.02 to 3, preferably 0.05 to 1.5. Theprepolymerization is carried out at a temperature of -20° to 80° C.,preferably 0° to 60° C., with a time of 0.5 to 100 hours, preferably 1to 50 hours.

The prepolymerized catalyst (1) can be prepared as described below.First, the carrier (component (c)) is suspended in the inerthydrocarbon. To the suspension, the organoaluminum oxy-compound catalystcomponent (component (b)) is introduced, and reacted for predeterminedperiod. Successively, supernatant is removed, and the resulting solidcomponent is re-suspended in the inert hydrocarbon. Into the system, thetransition metal compound catalyst component (component (a-1)) is addedand reacted for predetermined period. Then, supernatant is removed toobtain a solid catalyst component. Continuously, the solid catalystcomponent obtained above is added into inert hydrocarbon containing theorganoaluminum compound catalyst component (component (d)), and olefinis introduced therein to obtain the prepolymerized catalyst (1).

An amount of prepolymerized polyolefin produced in the prepolymerizationis, desirably based on 1 g of the carrier (c), of 0.1 to 500 g,preferably 0.2 to 300 g, more preferably 0.5 to 200 g. In theprepolymerized catalyst (1), component (a-1) is desirably supported inan amount in terms of transition metal atom, based on 1 g of the carrier(c), of about 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably 1×10⁻⁵ to 2×10⁻⁴ gatom. Further, a molecular ratio (Al/M) of aluminum atom (Al) derivedfrom components (b) and (d) to transition metal atom (M) derived fromcomponent (a-1) is usually 5 to 200, preferably 10 to 150.

The prepolymerization may be carried out either batchwise orcontinuously, and under reduced pressure, normal pressure or appliedpressure. During the prepolymerization, hydrogen may be allowed to bepresent to obtain a prepolymer desirably having an intrinsic viscosityη! of 0.2 to 7 dl/g, preferably 0.5 to 5 dl/g as measured in decalin atleast 135° C.

The ethylene/α-olefin copolymers A-1! used in the present invention areobtained by copolymerizing ethylene with an α-olefin having 3 to 20carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene in the presence of the olefinpolymerization catalyst (1) or the prepolymerized catalyst (1).

Copolymerization of ethylene and α-olefin is carried out in a gas phaseor liquid phase, for example, in slurry. In the slurry polymerization,an inactive hydrocarbon or the olefin itself may be used as a solvent.

Concrete examples of the inactive hydrocarbon solvent include aliphatichydrocarbons such as butane, isobutane, pentane, hexane, octane, decane,dodecane, hexadecane and octadecane; alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and cyclooctane; aromatichydrocarbons such as benzene, toluene and xylene; and petroleumfractions such as gasoline, kerosene and gas oil. Of these inactivehydrocarbons, preferred are aliphatic hydrocarbons, alicyclichydrocarbons and petroleum fractions.

When the copolymerization is carried out by the slurry method or the gasphase method, the olefin polymerization catalyst (1) or theprepolymerized catalyst (1) is used at such amount that theconcentration of the transition metal compound becomes usually 10⁻⁸ to10⁻³ g atom/liter, preferably 10⁻⁷ to 10⁻⁴ g atom/liter in terms of thetransition metal in the polymerization reaction system.

Furthermore, in the polymerization, an organoaluminum oxy-compoundsimilar to the catalyst component (b) and/or an organoaluminum compound(d) may be added. In this case, the atomic ratio (Al/M) of the aluminumatom (Al) derived from the organoaluminum oxy-compound and theorganoaluminum compound to the transition metal atom (M) derived fromthe transition metal compound catalyst component (a-1) is 5 to 300,preferably 10 to 200, more preferably 15 to 150.

When the ethylene/α-olefin copolymer A-1! is prepared by the slurrypolymerization, the polymerization temperature is usually -50° to 100°C., preferably 0° to 90° C. When the ethylene/α-olefin copolymer A-1! isprepared by the gas phase polymerization, the polymerization temperatureis usually 0° to 120° C., preferably 20° to 100° C.

The polymerization is carried out usually at a normal pressure to 100kg/cm², preferably under a pressure condition of 2 to 50 kg/cm². Thepolymerization can be carried out either batchwise, semicontinuously orcontinuously.

Furthermore, the polymerization may also be carried out in not less than2 steps having reaction conditions different from each other.

High-pressure radical polymerization low-density polyethylene B-1!!

The high-pressure radical polymerization low-density polyethylene B-1!used in the invention is a branched polyethylene having a number of longchain branches prepared by so-called high-pressure radicalpolymerization, and has a melt flow rate (MFR), as determined inaccordance with ASTM D1238-65T under the conditions of a temperature of190° C. and a load of 2.16 kg, of 0.1 to 50 g/10 min, preferably 0.2 to10 g/10 min, more preferably 0.2 to 8 g/10 min.

In the high-pressure radical polymerization low-density polyethyleneB-1! used in the invention, the index of the molecular weightdistribution (Mw/Mn, Mw=weight-average molecular weight,Mn=number-average molecular weight) measured by means of gel permeationchromatography (GPC) and the melt flow rate (MFR) satisfy the relation:

    Mw/Mn≧7.5×log (MFR)-1.2,

    preferably Mw/Mn≧7.5×log (MFR)-0.5,

    more preferably Mw/Mn≧7.5×log (MFR).

In the invention, the molecular weight distribution (Mw/Mn) of ahigh-pressure radical polymerization low-density polyethylene isdetermined as follows using GPC-150C produced by Milipore Co.

That is, in a column of TSK-GNH-HT having a diameter of 72 mm and alength of 600 mm, a sample (concentration: 0.1% by weight, amount: 500microliters) is moved under the conditions of a moving rate of 1.0ml/min and a column temperature of 140° C. using o-dichlorobenzene(available from Wako Junyaku Kogyo K.K.) as a mobile phase and 0.025% byweight of BHT (available from Takeda Chemical Industries, Ltd.) as anantioxidant. As a detector, a differential refractometer is used. Thestandard polystyrenes of Mw<1,000 and Mw>4×10⁶ are available from TosoCo., Ltd., and those of 1,000<Mw<4×10⁶ are available from PressureChemical Co.

The high-pressure radical polymerization low-density polyethylene B-1!used in the invention desirably has a density (d) of 0.910 to 0.930g/cm³.

In the invention, the density of a low-density polyethylene isdetermined by means of a density gradient tube using a strand which hasbeen obtained in the above-mentioned melt flow rate (MFR) measurementand which is treated by heating at 120° C. for 1 hour and slowly coolingto room temperature over 1 hour.

Further, in the high-pressure radical polymerization low-densitypolyethylene B-1! used in the invention, a swell ratio indicating adegree of the long chain branch, namely, a ratio (Ds/D) of a diameter(Ds) of a strand to an inner diameter (D) of a nozzle, is desirably notless than 1.3. The strand used herein is a strand extruded from a nozzlehaving an inner diameter (D) of 2.0 mm and a length of 15 mm at anextrusion rate of 10 mm/min and a temperature of 190° C. using acapillary type flow property tester.

The high-pressure radical polymerization low-density polyethylene B-1!as mentioned above may be a copolymer obtained by copolymerizingethylene with a polymerizable monomer such as other α-olefin, vinylacetate or acrylic ester, provided that the object of the invention isnot marred.

Ethylene copolymer composition!

The first ethylene copolymer composition according to the inventioncomprises the aforementioned ethylene/α-olefin copolymer A-1! and thehigh-pressure radical polymerization low-density polyethylene B-1!, anda weight ratio ( A-1!: B-1!) between the ethylene/α-olefin copolymerA-1! and the high-pressure radical polymerization low-densitypolyethylene B-1! is usually in the range of 99:1 to 60:40, preferably98:2 to 70:30, more preferably 98:2 to 80:20.

When the amount of the high-pressure radical polymerization low-densitypolyethylene B-1! is less than the lower limit of the above range, theresulting composition is sometimes improved insufficiently in thetransparency and the melt tension, and when the amount thereof is largerthan the upper limit of the above range, the resulting composition issometimes markedly deteriorated in the tensile strength and the stresscrack resistance.

The first ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The first ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-1!, the high-pressure radical polymerization low-density polyethyleneB-1!, and if necessary, other optional components by the use of anextruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-1!, the high-pressure radical polymerization low-density polyethyleneB-1!, and if necessary, other optional components in an appropriate goodsolvent (e.g., hydrocarbon solvent such as hexane, heptane, decane,cyclohexane, benzene, toluene and xylene), and then removing the solventfrom the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-1!, the high-pressure radical polymerization low-densitypolyethylene B-1!, and if necessary, other optional components in anappropriate good solvent to prepare solutions, then mixing thesolutions, and removing the solvent from the resulting mixture.

(4) A process of combining the above processes (1) to (3).

The first ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is excellent in transparency andmechanical strength, and has properties inherently belonging to generalLLDPE, such as heat-sealing properties, hot-tack properties, heatresistance and blocking resistance. Further, the film is free fromsurface stickiness because the ethylene/α-olefin copolymer A-1! has aprominently narrow composition distribution. Moreover, because of lowstress within the high-shear region, the ethylene copolymer compositioncan be extruded at a high speed, and consumption of electric power issmall, resulting in economical advantage.

Films obtained by processing the first ethylene copolymer composition ofthe invention are suitable for, for example, standard bags, heavy bags,wrapping films, materials for laminates, sugar bags, packaging bags foroily goods, packaging bags for moist goods, various packaging films suchas those for foods, bags for liquid transportation and agriculturalmaterials. The films may also be used as multi-layer films by laminatingthe films on various substrates such as a nylon substrate and apolyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.

Second ethylene copolymer composition!

The second ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer A-1! and acrystalline polyolefin B-2!.

Ethylene/α-olefin copolymer A-1!!

The ethylene/α-olefin copolymer A-1! employable for the second ethylenecopolymer composition is the same as the ethylene/α-olefin copolymerused for the first ethylene copolymer composition described above.

Crystalline polyolefin B-2!!

The crystalline polyolefin B-2! used in the invention is at least onecrystalline polyolefin selected from the following crystallinepolyolefins (B-I) to (B-III).

Crystallin polyolefine (B-I)

The crystalline polyolefin (B-I) used in the invention is an ethylenehomopolymer having a crystallinity measured by X-ray diffractometry ofnot less than 65%, or a copolymer of ethylene with an α-olefin of 3 to20 carbon atoms having the crystallinity of not less than 40%. Thecrystalline polyolefin (B-I) has a melt flow rate (MFR), as determinedin accordance with ASTM D1238-65T under the conditions of a temperatureof 190° C. and a load of 2.16 kg, of 0.01 to 100 g/10 min, preferably0.05 to 50 g/10 min, and has a density of not less than 0.900 g/cm³,preferably not less than 0.950 g/cm³, more preferably 0.960 to 0.970g/cm³.

The crystalline polyolefin (B-I) is prepared by using non-metallocenetype catalyst, preferably non-metallocene type Ziegler catalyst.

Examples of the α-olefin of 3 to 20 carbon atoms include propylene,1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-deceneand mixtures thereof. Of these, an α-olefin of 3 to 10 carbon atoms ispreferably employed. A molar ratio of ethylene to α-olefin(ethylene/α-olefin) in the copolymer varies depending on the kind of theα-olefin used, but generally is in the range of 100/0 to 99/1,preferably 100/0 to 99.5/0.5.

The crystalline polyolefin (B-I) used in the invention may containconstituent units other than the constituent units derived fromα-olefin, such as those derived from diene compounds, provided that theproperties of the crystalline polyolefin (B-1) are not marred.

Examples of the constituent units other than the constituent unitsderived from α-olefin include

constituent units derived from chain non-conjugated dienes such as1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene,6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene;

constituent units derived from cyclic non-conjugated dienes such ascyclohexadiene, dicyclopentadiene, methyltetrahydroindene,5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene,5-isopropylidene-2-norbornene and6-chloromethyl-5-isopropenyl-2-norbornene; and

constituent units derived from diene compounds such as2,3-diisopropylidene-5-norbornene,2-ethylidene-3-isopropylidene-5-norbornene and2-propenyl-2,2-norbornadiene.

The diene components may be used alone or in combination. The content ofthe diene component is usually in the range of 0 to 1% by mol,preferably 0 to 0.5% by mol.

The crystalline polyolefin (B-I) can be prepared by a known process.

Crystalline polyolefin (B-II)

The crystalline polyolefin (B-II) used in the invention is a propylenehomopolymer having a crystallinity measured by X-ray diffractometry ofnot less than 50%, or a copolymer of propylene with at least one olefinselected from ethylene and an α-olefin of 4 to 20 carbon atoms havingthe crystallinity of not less than 30%. The crystalline polyolefin(B-II) has a melt flow rate (MFR), as determined in accordance with ASTMD1238-65T under the conditions of a temperature of 230° C. and a load of2.16 kg, of 0.1 to 100 g/10 min, preferably 0.5 to 50 g/10 min, and hasa density of not less than 0.900 g/cm³, preferably 0.900 to 0.920 g/cm³.

Examples of the α-olefin of 4 to 20 carbon atoms include 1-butene,1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and mixturesthereof. Of these, an α-olefin of 4 to 10 carbon atoms is preferablyemployed.

In the copolymer of propylene with at least one of ethylene and α-olefinof 4 to 20 carbon atoms, a molar ratio of propylene to ethylene andα-olefin of 4 to 20 carbon atoms (propylene/α-olefin, α-olefin includesethylene) varies depending on the kind of the α-olefin used, butgenerally is in the range of 100/0 to 90/10, preferably 100/0 to 95/5.

The crystalline polyolefin (B-II) used in the invention may containconstituent units derived from the diene compounds employable for theaforesaid crystalline polyolefin (B-I), provided that the properties ofthe crystalline polyolefin (B-II) are not marred. The content of thediene component is usually in the range of 0 to 1% by mol, preferably 0to 0.5% by mol.

The crystalline polyolefin (B-II) can be prepared by a known process.

Crystalline polyolefine (B-III)

The crystalline polyolefin (B-III) used in the invention is ahomopolymer of an α-olefin of 4 to 20 carbon atoms having acrystallinity measured by X-ray diffractometry of not less than 30%, ora copolymer of α-olefins of 4 to 20 carbon atoms having thecrystallinity of not less than 30%. The crystalline polyolefin (B-III)has a melt flow rate (MFR), as determined in accordance with ASTMD1238-65T under the conditions of a temperature of 230° C. and a load of2.16 kg, of 0.1 to 100 g/10 min, preferably 0.5 to 50 g/10 min, and hasa density of not less then 0.900 g/cm³, preferably 0.900 to 0.920 g/cm³.

Examples of the α-olefin of 4 to 20 carbon atoms include 1-butene,1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. Ofthese, an α-olefin of 4 to 10 carbon atoms is preferably employed.

In the copolymer comprising at least two kinds of α-olefins of 4 to 20carbon atoms, a molar ratio ((a)/(b)) of one α-olefin (a) selected fromα-olefins of 4 to 20 carbon atoms to the other α-olefin (b) selectedfrom α-olefins of 4 to 20 carbon atoms varies depending on the kind ofthe α-olefins used, but generally is in the range of 100/0 to 90/10,preferably 100/0 to 95/5.

The crystalline polyolefin (B-III) used in the invention may containconstituent units derived from the diene compounds employable for theaforesaid crystalline polyolefin (B-I), provided that the properties ofthe crystalline polyolefin (B-III) are not marred. The content of thediene component is usually in the range of 0 to 1% by mol, preferably 0to 0.5% by mol.

The crystalline polyolefin (B-III) can be prepared by a known process.

Ethylene copolymer composition!

The second ethylene copolymer composition according to the inventioncomprises the aforementioned ethylene/α-olefin copolymer A-1! and thecrystalline polyolefin B-2!, and a weight ratio ( A-1!: B-2!) betweenthe ethylene/α-olefin copolymer A-1! and the crystalline polyolefin B-2!is usually in the range of 99:1 to 60:40, preferably 98:2 to 70:30, morepreferably 95:5 to 80:20.

The second ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The second ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-1!, the crystalline polyolefin B-2!, and if necessary, other optionalcomponents by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-1!, the crystalline polyolefin B-2!, and if necessary, other optionalcomponents in an appropriate good solvent (e.g., hydrocarbon solventsuch as hexane, heptane, decane, cyclohexane, benzene, toluene andxylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-1!, the crystalline polyolefin B-2!, and if necessary, otheroptional components in an appropriate good solvent to prepare solutions,then mixing the solutions, and removing the solvent from the resultingmixture.

(4) A process of combining the above processes (1) to (3).

The second ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is well-balanced between thetransparency and the rigidity, and has properties inherently belongingto general LLDPE, such as heat-sealing properties, hot-tack propertiesand heat resistance. Further, the film is free from surface stickinessbecause the ethylene/α-olefin copolymer A-1! has a prominently narrowcomposition distribution. Moreover, because of low stress within thehigh-shear region, the ethylene copolymer composition can be extruded ata high speed, and consumption of electric power is small, resulting ineconomical advantage.

Films obtained by processing the second ethylene copolymer compositionof the invention are suitable for, for example, standard bags, heavybags, wrapping films, materials for laminates, sugar bags, packagingbags for oily goods, packaging bags for moist goods, various packagingfilms such as those for foods, bags for liquid transportation andagricultural materials. The films may also be used as multi-layer filmsby laminating the films on various substrates such as a nylon substrateand a polyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.Particularly, the films are most suitable for liquid transportationbags.

Third ethylene copolymer composition!

The third ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer A-1! and an olefintype elastomer B-3!.

Ethylene/α-olefin copolymer A-1!!

The ethylene/α-olefin copolymer A-1! employable for the third ethylenecopolymer composition is the same as the ethylene/α-olefin copolymerused for the first ethylene copolymer composition described before.

Olefin type elastomer B-3!!

The olefin type elastomer B-3! used in the invention is a polymer ofethylene or an α-olefin of 3 to 20 carbon atoms, or a copolymer of twoor more kinds of olefins selected from ethylene and α-olefins of 3 to 20carbon atoms. The olefin type elastomer B-3! has a density of not morethan 0.900 g/cm³, preferably 0.860 to 0.900 g/cm³, and has a melt flowrate (MFR), as determined in accordance with ASTM D1238-65T under theconditions of a temperature of 190° C. and a load of 2.16 kg, of 0.01 to100 g/10 min, preferably 0.05 to 50 g/10 min. The olefin type elastomerB-3! desirably has a crystallinity measured by X-ray diffractometry ofless than 30%, or desirably is amorphous.

Examples of the α-olefin of 3 to 20 carbon atoms include propylene,1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-deceneand mixtures thereof. Of these, an α-olefin having 3 to 10 carbon atomsis preferably employed.

The olefin type elastomer B-3! used in the invention may containconstituent units other than the constituent units derived fromα-olefin, such as those derived from diene compounds, provided that theproperties of the olefin type elastomer are not marred.

Examples of the constituent units which may be contained in the olefintype elastomer used in the invention include

constituent units derived from chain non-conjugated dienes such as1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene,6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene;

constituent units derived from cyclic non-conjugated dienes such ascyclohexadiene, dicyclopentadiene, methyltetrahydroindene,5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene,5-isopropylidene-2-norbornene and6-chloromethyl-5-isopropenyl-2-norbornene; and

constituent units derived from diene compounds such as2,3-diisopropylidene-5-norbornene,2-ethylidene-3-isopropylidene-5-norbornene and2-propenyl-2,2-norbornadiene.

The diene components may be used alone or in combination. The content ofthe diene component is usually not more than 10% by mol, preferably inthe range of 0 to 5% by mol.

A concrete example of the olefin type elastomer B-3!is a copolymercomprising

constituent units derived from ethylene in an amount of 0 to 95% by mol,preferably 30 to 92% by mol, more preferably 50 to 90% by mol,

constituent units derived from an α-olefin of 3 to 20 carbon atoms in anamount of 1 to 100% by mol, preferably 4 to 70% by mol, more preferably8 to 50% by mol, and

constituent units derived from a diene component in an amount of 0 to10% by mol, preferably 0 to 5% by mol, more preferably 0 to 3% by mol.

The olefin type elastomer B-3! can be prepared by a known process usinga catalyst of Ti type, V type, Zr type, etc.

Ethylene copolymer composition!

The third ethylene copolymer composition according to the presentinvention comprises the aforementioned ethylene/α-olefin copolymer A-1!and the olefin type elastomer B-3!, and a weight ratio ( A-1!: B-3!)between the ethylene/α-olefin copolymer A-1! and the olefin typeelastomer B-3! is usually in the range of 99:1 to 60:40, preferably 95:5to 70:30, more preferably 98:2 to 80:20. Further, the ethylene/α-olefincopolymer A-1! and the olefin type elastomer B-3! are appropriatelyselected so that a density ratio ( B-3!/ A-1!) of the olefin typeelastomer B-3! to the ethylene/α-olefin copolymer A-1! is less than 1,preferably in the range of 0.905 to 0.980.

The third ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The third ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-1!, the olefin type elastomer B-3!, and if necessary, other optionalcomponents by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-1!, the olefin type elastomer B-3!, and if necessary, other optionalcomponents in an appropriate good solvent (e.g., hydrocarbon solventsuch as hexane, heptane, decane, cyclohexane, benzene, toluene andxylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-1!, the olefin type elastomer B-3!, and if necessary, otheroptional components in an appropriate good solvent to prepare solutions,then mixing the solutions, and removing the solvent from the resultingmixture.

(4) A process of combining the above processes (1) to (3).

The third ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is well-balanced between thetransparency and the rigidity, and has properties inherently belongingto general LLDPE, such as heat-sealing properties, hot-tack propertiesand heat resistance. Further, the film is free from surface stickinessbecause the ethylene/α-olefin copolymer A-1! has a prominently narrowcomposition distribution. Moreover, because of low stress within thehigh-shear region, the ethylene copolymer composition can be extruded ata high speed, and consumption of electric power is small, resulting ineconomical advantage.

Films obtained by processing the third ethylene copolymer composition ofthe invention are suitable for, for example, standard bags, heavy bags,wrapping films, materials for laminates, sugar bags, packaging bags foroily goods, packaging bags for moist goods, various packaging films suchas those for foods, bags for liquid transportation and agriculturalmaterials. The films may also be used as multi-layer films by laminatingthe films on various substrates such as a nylon substrate and apolyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.Particularly, the films are most suitable as wrapping films.

Fourth ethylene copolymer composition!

The fourth ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer composition Ia! whichcomprises an ethylene/α-olefin copolymer A-2! and an ethylene/α-olefincopolymer A-3!, and a high pressure radical polymerization low-densitypolyethylene IIa!.

Ethylene/α-olefin copolymer A-2!!

The ethylene/α-olefin copolymer A-2! for forming the fourth ethylenecopolymer composition of the invention is a random copolymer of ethylenewith an α-olefin of 3 to 20 carbon atoms. Examples of the α-olefin of 3to 20 carbon atoms employable for copolymerization with ethylene includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and1-eicosene.

In the ethylene/α-olefin copolymer A-2!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, and constituent units derived from α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

The ethylene/α-olefin copolymer A-2! has the following properties (i) to(vi).

(i) The density (d) is usually in the range of 0.880 to 0.940 g/cm³,preferably 0.890 to 0.935 g/cm³, more preferably 0.900 to 0.930 g/cm³.

(ii) The intrinsic viscosity η_(A-2) ! as measured in decalin at 135° C.is in the range of 1.0 to 10.0 dl/g, preferably 1.25 to 8 dl/g, morepreferably 1.27 to 6 dl/g.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

(iv) The melt tension (MT (g)) at 190° C. and the melt flow rate (MFR)satisfy the relation:

    MT>2.2×MFR.sup.-0.84.

The ethylene/α-olefin copolymer A-2! as mentioned above which is usedfor the invention has high melt tension (MT) and good moldability.

(v) The flow index (FI (l/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation:

    FI>75×MFR,

    preferably FI>100×MFR,

    more preferably FI>120×MFR.

The ethylene/α-olefin copolymer A-2! whose FI and MFR satisfy theabove-mentioned relation shows a small processing torque because a lowstress can be kept even at a high-shear rate, and has good moldability.

(vi) The fraction of a n-decane-soluble component at room temperature (W% by weight) and the density (d) satisfy the relation:

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1.

It may be concluded from the relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the fraction (W) of a n-decane-soluble component andthe density (d), that the ethylene/α-olefin copolymer A-2! has a narrowcomposition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-2! desirably is not more than 0.5 per1,000 carbon atoms and less than 1 per one molecule of the copolymer.

The ethylene/α-olefin copolymer A-2! having the properties as mentionedabove can be prepared by copolymerizing ethylene with an α-olefin of 3to 20 carbon atoms in the presence of the aforementioned olefinpolymerization catalyst (1) or prepolymerized catalyst (1) under thesame conditions as those for preparing the ethylene/α-olefin copolymerA-1! in such a manner that the resulting copolymer would have a densityof 0.880 to 0.940 g/cm³.

When a slurry polymerization process is used for preparing theethylene/α-olefin copolymer A-2!, the polymerization temperature isusually in the range of -50° to 90° C., preferably 0° to 80° C., andwhen a gas phase polymerization process is used therefor, thepolymerization temperature is usually in the range of 0° to 90° C.,preferably 20° to 80° C.

Ethylene/α-olefin copolymer A-3!!

The ethylene/α-olefin copolymer A-3! for forming the fourth ethylenecopolymer composition of the invention is a random copolymer of ethyleneand an α-olefin of 3 to 20 carbon atoms. Examples of the α-olefin of 3to 20 carbon atoms employable for copolymerization with ethylene includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and1-eicosene.

In the ethylene/α-olefin copolymer A-3!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, 5 and constituent units derived from α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

The ethylene/α-olefin copolymer A-3! has the following properties (i) to(iv).

(i) The density (d) is usually in the range of 0.910 to 0.960 g/cm³,preferably 0.915 to 0.955 g/cm³, more preferably 0.920 to 0.950 g/cm³.

(ii) The intrinsic viscosity η_(A-3) ! as measured in decalin at 135° C.is in the range of 0.5 to 2.0 dl/g, preferably 0.55 to 1.9 dl/g, morepreferably 0.6 to 1.8 dl/g.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

(iv) The fraction of a n-decane-soluble component at room temperature (W% by weight) and the density (d) satisfy the relation:

in the case of MFR≧10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1,

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1.

It may be concluded from the relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the fraction (W) of a n-decane-soluble component andthe density (d), that the ethylene/α-olefin copolymer A-3! has a narrowcomposition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-3! desirably is not more than 0.5 per1,000 carbon atoms and less than 1 per one molecule of the copolymer.

The ethylene/α-olefin copolymer A-3! having the properties as mentionedabove can be prepared by copolymerizing ethylene and an α-olefin of 3 to20 carbon atoms in the presence of an olefin polymerization catalyst (2)or a prepolymerized catalyst (2) formed from (a-2) a transition metalcompound catalyst component, (b) an organoaluminum oxy-compound catalystcomponent, (c) a carrier, and if necessary, (d) an organoaluminumcompound catalyst component, all components being described later, insuch a manner that the resulting copolymer would have a density of 0.910to 0.960 g/cm³.

First, the transition metal compound catalyst component (a-2) isexplained below.

The transition metal compound catalyst component (a-2) (sometimesreferred to as "component (a-2)" hereinafter) is a compound of atransition metal in Group IV of the periodic table which contains aligand having a cyclopentadienyl skeleton. There is no specificlimitation on the component (a-2), as far as it is a compound of atransition metal in Group IV of the periodic table which contains aligand having a cyclopentadienyl skeleton. However, the component (a-2)preferably is a transition metal compound represented by the followingformula V!.

    ML.sub.X                                                    V!

wherein M is a transition metal atom selected from Group IVB of theperiodic table, L is a ligand coordinating to the transition metal, atleast one of L is a ligand having a cyclopentadienyl skeleton, L otherthan the ligand having a cyclopentadienyl skeleton is a hydrocarbongroup of 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, atrialkylsilyl group, a SO₃ R group (R is a hydrocarbon group of 1 to 8carbon atoms which may have a substituent group such as halogen), ahalogen atom or a hydrogen atom, and X is a valance of the transitionmetal.

The transition metal compound represented by the above formula V!includes the transition metal compound represented by the formula I! andthe transition metal compound represented by the formula II! which arecited before as the transition metal catalyst component (a-1).

In the above-mentioned formula V!, M is a transition metal selected fromGroup IVB of the periodic table, and concrete preferable examples of Minclude zirconium, titanium and hafnium. Of these, particularlypreferred is zirconium.

The ligands having a cyclopentadienyl skeleton include, for example,cyclopentadienyl; an alkyl-substituted cyclopentadienyl group such as

methylcyclopentadienyl, dimethylcyclopentadienyl,trimethylcyclopentadienyl, tetramethylcyclopentadienyl,pentamethylcyclopentadienyl, ethylcyclopentadienyl,methylethylcyclopentadienyl, propylcyclopentadienyl,methylpropylcyclopentadienyl, butylcyclopentadienyl,methylbutylcyclopentadienyl and hexylcyclopentadienyl; indenyl,4,5,6,7-tetrahydroindenyl and fluorenyl. These groups may be substitutedwith halogen atom or trialkylsilyl group, and the like.

Of these ligands coordinated to the transition metal, particularlypreferred is the alkyl-substituted cyclopentadienyl group.

When the compound represented by the above formula V! contains two ormore of the groups having a cyclopentadienyl skeleton, two of them eachhaving a cyclopentadienyl skeleton can be bonded together through analkylene group (e.g., ethylene and propylene), a substituted alkylenegroup such as isopropylidene and diphenylmethylene, a silylene group, ora substituted silylene group such as dimethylsilylene, diphenylsilyleneand methylphenylsilylene.

Concrete examples of the ligand L other than those having acyclopentadienyl skeleton are as follows:

The hydrocarbon group having 1 to 12 carbon atoms includes, for example,an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group,and concrete examples of these groups are as follows;

an alkyl group such as methyl, ethyl, propyl, isopropyl and butyl;

a cycloalkyl group such as cyclopentyl and cyclohexyl;

an aryl group such as phenyl and tolyl;

an aralkyl group such as benzyl and neophyl;

an alkoxy group such as methoxy, ethoxy and butoxy;

an aryloxy group such as phenoxy; and

halogen such as fluorine, chlorine, bromine and iodine.

The ligand represented by SO₃ R includes, for example,p-toluenesulfonate, methanesulfonate and trifluoromethanesulfonate.

Such a metallocene compound containing ligands each having acyclopentadienyl skeleton (e.g. having a transition metal with a valenceof 4) may be represented more concretely by the formula V'!

    R.sup.2 kR.sup.3 lR.sup.4 mR.sup.5 nM                       IV'!

wherein M is a transition metal as mentioned above, R² is a group havinga cyclopentadienyl skeleton (ligand), R³, R⁴ and R⁵ are each a grouphaving a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group,an aryl group, an aralkyl group, an alkoxy group, an aryloxy group,trialkylsilyl group, SO₃ ^(R) group, halogen or hydrogen, k is aninteger of not less than 1, and k+l+m+n=4.

As the component (a-2), preferred is the metallocene compoundrepresented by the above formula V'! in which at least two of R², R³, R⁴and R⁵, that is, R² and R³ are each a group having a cyclopentadienylskeleton (ligand). Said groups having a cyclopentadienyl skeleton may bebonded together through a group such as an alkylene group (e.g.,ethylene and propylene), a substituted alkylene group such asisopropylidene and diphenylmethylene, a silylene group, and asubstituted silylene group such as dimethylsilylene, diphenylsilyleneand methylphenylsilylene. Further, R⁴ and R⁵ are each a group having acyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, an alkoxy group, an aryloxy group,trialkylsilyl group, SO₃ R group, halogen or hydrogen.

Listed below are concrete examples of the transition metal compoundhaving zirconium as M.

Bis(indenyl)zirconium dichloride,

Bis(indenyl)zirconium dibromide,

Bis(indenyl)zirconium bis(p-toluenesulfonate),

Bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Bis(fluorenyl)zirconium dichloride,

Ethylenebis(indenyl)zirconium dichloride,

Ethylenebis(indenyl)zirconium dibromide,

Ethylenebis(indenyl)dimethylzirconium,

Ethylenebis(indenyl)diphenylzirconium,

Ethylenebis(indenyl)methylzirconium monochloride,

Ethylenebis(indenyl)zirconium bis(methanesulfonate),

Ethylenebis(indenyl)zirconium bis(p-toluenesulfonate),

Ethylenebis(indenyl)zirconium bis(trifluoromethanesulfonate),

Ethylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Isopropylidene(cyclopentadienylfluorenyl)zirconium dichloride,

Isopropylidene(cyclopentadienyl-methylcyclopentadienyl)zirconiumdichloride,

Dimethylsilylenebis(cyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(methylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(dimethylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(trimethylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(indenyl)zirconium dichloride,

Dimethylsilylenebis(indenyl)zirconium bis(trifluoromethanesulfonate),

Dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Dimethylsilylenebis(cyclopentadienyl-fluorenyl)zirconium dichloride,

Diphenylsilylenebis(indenyl)zirconium dichloride,

Methylphenylsilylenebis(indenyl)zirconium dichloride,

Bis(cyclopentadienyl)zirconium dichloride,

Bis(cyclopentadienyl)zirconium dibromide,

Bis(cyclopentadienyl)methylzirconium monochloride,

Bis(cyclopentadienyl)ethylzirconium monochloride,

Bis(cyclopentadienyl)cyclohexylzirconium monochloride,

Bis(cyclopentadienyl)phenylzirconium monochloride,

Bis(cyclopentadienyl)benzylzirconium monochloride,

Bis(cyclopentadienyl)zirconium monochloride monohydride,

Bis(cyclopentadienyl)methylzirconium monohydride,

Bis(cyclopentadienyl)dimethylzirconium,

Bis(cyclopentadienyl)diphenylzirconium,

Bis(cyclopentadienyl)dibenzylzirconium,

Bis(cyclopentadienyl)zirconium methoxychloride,

Bis(cyclopentadienyl)zirconium ethoxychloride,

Bis(cyclopentadienyl)zirconium bis(methanesulfonate),

Bis(cyclopentadienyl)zirconium bis(p-toluenesulfonate),

Bis(cyclopentadienyl)zirconium bis(trifluoromethanesulfonate),

Bis(methylcyclopentadienyl)zirconium dichloride,

Bis(dimethylcyclopentadienyl)zirconium dichloride,

Bis(dimethylcyclopentadienyl)zirconium ethoxychloride,

Bis(dimethylcyclopentadienyl)zirconium bis(trifluoromethanesulfonate),

Bis(ethylcyclopentadienyl)zirconium dichloride,

Bis(methylethylcyclopentadienyl)zirconium dichloride,

Bis(propylcyclopentadienyl)zirconium dichloride,

Bis(methylpropylcyclopentadienyl)zirconium dichloride,

Bis(butylcyclopentadienyl)zirconium dichloride,

Bis(methylbutylcyclopentadienyl)zirconium dichloride,

Bis(methylbutylcyclopentadienyl)zirconium bis(methanesulfonate),

Bis(trimethylcyclopentadienyl)zirconium dichloride,

Bis(tetramethylcyclopentadienyl)zirconium dichloride,

Bis(pentamethylcyclopentadienyl)zirconium dichloride,

Bis(hexylcyclopentadienyl)zirconium dichloride, and

Bis(trimethylsilylcyclopentadienyl)zirconium dichloride.

In the above exemplified compounds, di-substituted cyclopentadienylinclude 1,2- and 1,3-substituted, and tri-substituted include 1,2,3- and1,2,4-substituted. Further, the alkyl group such as propyl or butylincludes n-, i-, sec- and tert- isomers.

There may also be used transition metal compounds obtained bysubstituting titanium or hafnium for zirconium in the above-exemplifiedzirconium compounds.

The above listed compounds, the transition metal compounds representedby the above formula I! and the transition metal compounds representedby the above formula II! are used as transition metal catalyst component(a-2). Preferred are the above mentioned transition metal compoundsrepresented by the formula I! or II!. Of these, particularly preferredis

Ethylenebis(indenyl)zirconium dichloride,

Ethylenebis(4-methyl-1-indenyl)zirconium dichloride,

Ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride,

Bis(1,3-dimethylcyclopentadienyl)zirconium dichloride,

Bis(1,3-diethylcyclopentadienyl)zirconium dichloride, or

Bis(1-methyl-3-ethylcyclopentadienyl)zirconium dichloride.

Further, the transition metal catalyst component (a-1) used in thepreparation of the ethylene/α-olefin copolymer A-2! and the transitionmetal catalyst component (a-2) used in the preparation of theethylene/α-olefin copolymer A-3! are preferably the same compounds.

The organoaluminum oxy-compound catalyst component (b) component (b)!which forms the olefin polymerization catalyst (2) is the same as theorganoluminum oxy-compound which forms the above mentioned olefinpolymerization catalyst (1).

The carrier (c) component (c)! which forms the olefin polymerizationcatalyst (2) is the same as the carrier which forms the above mentionedolefin polymerization catalyst (1).

The optionally used organoaluminum compound catalyst component (d)component (d)! is the same as the organoaluminum compound which formsthe above mentioned olefin polymerization catalyst (1).

The ethylene/α-olefin copolymer A-3! used in the present invention canbe prepared by the olefin polymerization catalyst (2) formed bycontacting the above-mentioned components (a-2), (b), (c) and ifnecessary, component (d). Though the mixing of these components (a-2),(b), (c) and (d) may be conducted in arbitrarily selected order, themixing and contacting is preferably conducted in the order of:

mixing and contacting the components (b) and (c), followed by mixing andcontacting the component (a-2), and if necessary, mixing and contactingthe component (d).

The mixing of the above-mentioned components (a-2), (b), (c) and (d) canbe carried out in an inert hydrocarbon.

As the inert hydrocarbon solvent, there may be mentioned an aliphatichydrocarbon, such as propane, butane, pentane, hexane, heptane, octane,decane, dodecane and kerosene;

an alicyclic hydrocarbon, such as cyclopentane, cyclohexane andmethylcyclopentane;

an aromatic hydrocarbon, such as benzene, toluene and xylene;

a halogenated hydrocarbon, such as ethylene chloride, chlorobenzene anddichloromethane; and a mixture thereof.

In the contacting and mixing of the components (a-2), (b), (c) and ifneccessary (d), the component (a-2) is used usually in an amount of5×10⁻⁶ to 5×10⁻⁴ mol, preferably 1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g ofthe component (c), and the concentration thereof is 1×10⁻⁴ to 2×10⁻²mol/l, preferably 2×10⁻⁴ to 1×10⁻² mol/l. atomic ratio (Al/transitionmetal) of the aluminum in the component (b) to the transition metal inthe component (a-2) is usually 10 to 500, preferably 20 to 200. Theatomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) in the component(d) optionally used to the aluminum atoms (Al-b) in the component (b) isusually 0.02 to 3, preferably 0.05 to 1.5.

The components (a-2), (b) and (c), and if necessary, the component (d)are mixed and contacted at a temperature of usually -50° to 150° C.,preferably -20° to 120° C., with a contact time of 1 minute to 50 hours,preferably 10 minutes to 25 hours.

In the catalyst (2) for olefin polymerization obtained as describedabove, it is desirable that the transition metal derived from component(a-2) is supported in an amount of 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably1×10⁻⁵ to 2×10⁻⁴ g atom, and aluminum derived from components (b) and(d) is supported in an amount of 10⁻³ to 5×10⁻² g atom, preferably2×10⁻³ to 2×10⁻² g atom, all the amounts being based on 1 g of thecomponent (c).

Further, the catalyst for preparing the ethylene/α-olefin copolymer A-3!used in the present invention may be a prepolymerized catalyst (2)obtained by prepolymerization of olefin in the presence of theabove-mentioned components (a-2), (b) and (c), and if necessary, (d).

The prepolymerized catalyst (2) can be prepared by mixing the component(a-2), the component (b), the component (c), and if necessary, thecomponent (d), introducing olefin to the resulting mixture in the inerthydrocarbon solvent, and carrying out prepolymerization.

The olefins which can be prepolymerized include ethylene and α-olefinseach having 3 to 20 carbon atoms, for example, propylene, 1-butene,1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodeceneand 1-tetradecene. Of these, particularly preferred is ethylene or thecombination of ethylene and α-olefin used in the polymerization.

During the prepolymerization, the component (a-2) is used usually in aconcentration of is 1×10⁻⁶ to 2×10⁻² mol/l, preferably 5×10⁻⁵ to 1×10⁻²mol/l and amount thereof is usually 5×10⁻⁶ to 5×10⁻⁴ mol, preferably1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g of the component (c). The atomic ratio(Al/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-2) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5. Theprepolymerization is carried out at a temperature of -20° to 80° C.,preferably 0° to 60° C., with a time of 0.5 to 100 hours, preferably 1to 50 hours.

The prepolymerized catalyst (2) can be prepared as described below.First, the carrier (component (c)) is suspended in the inerthydrocarbon. To the suspension, the organoaluminum oxy-compound catalystcomponent (component (b)) is introduced, and reacted for predeterminedperiod. Successively, supernatant is removed, and the resulting solidcomponent is re-suspended in the inert hydrocarbon. Into the system, thetransition metal compound catalyst component (component (a-2)) is addedand reacted for predetermined period. Then, supernatant is removed toobtain a solid catalyst component. Continuously, the solid catalystcomponent obtained above is added into inert hydrocarbon containing theorganoaluminum compound catalyst component (component (d)), and olefinis introduced therein to obtain the prepolymerized catalyst (2).

An amount of prepolymerized polyolefin produced in the prepolymerizationis, desirably based on 1 g of the carrier (c), of 0.1 to 500 g,preferably 0.2 to 300 g, more preferably 0.5 to 200 g. In theprepolymerized catalyst (2), component (a-2) is desirably supported inan amount in terms of transition metal atom, based on 1 g of the carrier(c), of about 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably 1×10⁻⁵ to 2×10⁻⁴ gatom. Further, a molecular ratio (Al/M) of aluminum atom (Al) derivedfrom components (b) and (d) to transition metal atom (M) derived fromcomponent (a-2) is usually 5 to 200, preferably 10 to 150.

The prepolymerization may be carried out either batchwise orcontinuously, and under reduced pressure, normal pressure or appliedpressure. During the prepolymerization, hydrogen may be allowed to bepresent to obtain a prepolymer desirably having an intrinsic viscosityη! of 0.2 to 7 dl/g, preferably 0.5 to 5 dl/g as measured in decalin atleast 135° C.

The ethylene/α-olefin copolymers A-3! used in the present invention areobtained by copolymerizing ethylene with an α-olefin having 3 to 20carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene in the presence of the olefinpolymerization catalyst (2) or the prepolymerized catalyst (2).

Copolymerization of ethylene and α-olefin is carried out in a gas phaseor liquid phase, for example, in slurry. In the slurry polymerization,an inactive hydrocarbon or the olefin itself may be used as a solvent.

Concrete examples of the inactive hydrocarbon solvent include aliphatichydrocarbons such as butane, isobutane, pentane, hexane, octane, decane,dodecane, hexadecane and octadecane; alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and cyclooctane; aromatichydrocarbons such as benzene, toluene and xylene; and petroleumfractions such as gasoline, kerosene and gas oil. Of these inactivehydrocarbons, preferred are aliphatic hydrocarbons, alicyclichydrocarbons and petroleum fractions.

When the copolymerization is carried out by the slurry method or the gasphase method, the olefin polymerization catalyst (2) or theprepolymerized catalyst (2) is used at such amount that theconcentration of the transition metal compound becomes usually 10⁻⁸ to10⁻³ g atom/liter, preferably 10⁻⁷ to 10⁻⁴ g atom/liter in terms of thetransition metal in the polymerization reaction system.

Furthermore, in the polymerization, an organoaluminum oxy-compoundsimilar to the catalyst component (b) and/or an organoaluminum compound(d) may be added. In this case, the atomic ratio (Al/M) of the aluminumatom (Al) derived from the organoaluminum oxy-compound and theorganoaluminum compound to the transition metal atom (M) derived fromthe transition metal compound catalyst component (a-2) is 5 to 300,preferably 10 to 200, more preferably 15 to 150.

When the ethylene/α-olefin copolymer A-3! is prepared by the slurrypolymerization, the polymerization temperature is usually -30° to 100°C., preferably 20° to 90° C. When the ethylene/α-olefin copolymer A-3!is prepared by the gas phase polymerization, the polymerizationtemperature is usually 20° to 120° C., preferably 40° to 100° C.

The polymerization is carried out usually at a normal pressure to 100kg/cm², preferably under a pressure condition of 2 to 50 kg/cm². Thepolymerization can be carried out either batchwise, semicontinuously orcontinuously.

Ethylene/α-olefin copolymer composition Ia!!

The ethylene/α-olefin copolymer composition Ia!comprises theethylene/α-olefin copolymer A-2! and the ethylene/α-olefin copolymerA-3!. In this composition Ia!, the ethylene/α-olefin copolymer A-2! iscontained in an amount of 5 to 95% by weight, preferably 10 to 90% byweight, and the ethylene/α-olefin copolymer A-3! is contained in anamount of 5 to 95% by weight, preferably 10 to 90% by weight.

The ethylene/α-olefin copolymer A-2! and the ethylene/α-olefin copolymerA-2! are appropriately combined so that a density ratio ( A-2!/ A-3!) ofthe ethylene/R-olefin copolymer A-2! to the ethylene/α-olefin copolymerA-3! is less than 1, preferably in the range of 0.930 to 0.999. Further,they are also appropriately combined so that a ratio ( η_(A-2) !/η_(A-3) !) of the intrinsic viscosity η_(A-2) ! of the ethylene/α-olefincopolymer A-2! to the intrinsic viscosity η_(A-3) ! of theethylene/α-olefin copolymer A-3! is not less than 1, preferably in therange of 1.05 to 10, more preferably 1.1 to 5.

The ethylene/α-olefin copolymer composition has a density of usually0.890 to 0.955 g/cm³, preferably 0.905 to 0.950 g/cm³, and has amelt-flow rate (MFR), as determined in accordance with ASTM D1238-65Tunder the conditions of a temperature of 190° C. and a load of 2.16 kg,of 0.1 to 100 g/10 min, preferably 0.2 to 50 g/10 min.

The ethylene/α-olefin copolymer composition Ia! can be prepared by knownprocesses, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-2!, the ethylene/α-olefin copolymer A-3!, and if necessary, otheroptional components by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-2!, the ethylene/α-olefin copolymer A-3!, and if necessary, otheroptional components in an appropriate good solvent (e.g., hydrocarbonsolvent such as hexane, heptane, decane, cyclohexane, benzene, tolueneand xylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-2!, the ethylene/α-olefin copolymer A-3!, and if necessary,other optional components in an appropriate good solvent to preparesolutions, then mixing the solutions, and removing the solvent from theresulting mixture.

(4) A process in any combination of the above processes (1) to (3).

Further, the ethylene/α-olefin copolymer composition Ia! may be preparedby forming the ethylene/α-olefin copolymer A-2! and theethylene/α-olefin copolymer A-3! in two or more copolymerization stageshaving reaction conditions different from each other, or may be preparedby separately forming the ethylene/α-olefin copolymer A-2! and theethylene/α-olefin copolymer A-3! by the use of plural polymerizers.

High-pressure radical polymerization low-density polyethylene IIa!!

As the high-pressure radical polymerization low-density polyethyleneIIa! employable for the fourth ethylene copolymer composition may be thesame as the high-pressure radical polymerization low-densitypolyethylene B-1! used for the first ethylene copolymer composition.

Ethylene copolymer composition!

The fourth ethylene copolymer composition according to the presentinvention comprises the ethylene/α-olefin copolymer composition Ia! andthe high-pressure radical polymerization low-density polyethylene IIa!.It is desirable that a weight ratio ( Ia!: IIa!) between theethylene/α-olefin copolymer composition Ia! and the high-pressureradical polymerization low-density polyethylene IIa! is usually in therange of 99:1 to 60:40, preferably 98:2 to 70:30, more preferably 98:2to 80:20.

When the amount of the high-pressure radical polymerization low-densitypolyethylene is less than the lower limit of the above range, theresulting composition may be improved insufficiently in the transparencyand the melt tension. On the other hand, when the amount thereof islarger than the upper limit of the above range, the resultingcomposition may considerably be deteriorated in the tensile strength andthe stress crack resistance.

The fourth ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, anti-fogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The fourth ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymercomposition Ia!, the high-pressure radical polymerization low-densitypolyethylene IIa!, and if necessary, other optional components by theuse of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymercomposition Ia!, the high-pressure radical polymerization low-densitypolyethylene IIa!, and if necessary, other optional components in anappropriate good solvent (e.g., hydrocarbon solvent such as hexane,heptane, decane, cyclohexane, benzene, toluene and xylene), and thenremoving the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer composition Ia!, the high-pressure radical polymerizationlow-density polyethylene IIa!, and if necessary, other optionalcomponents in an appropriate good solvent to prepare solutions, thenmixing the solutions, and removing the solvent from the resultingmixture.

(4) A process in any combination of the above processes (1) to (3).

The fourth ethylene copolymer composition according to the presentinvention may be processed by a conventional molding method, forexample, air-cooling inflation molding, two-stage air-cooling inflationmolding, high-speed inflation molding, T-die film molding, water-coolinginflation molding or the like, to obtain a film. The film thus obtainedhas excellent transparency, mechanical strength and blocking resistance,and retains properties inherent in general LLDPE, such as heat-sealingproperties, hot-tack properties and heat resistance. Further, the filmis free from surface stickiness because each of the ethylene/α-olefincopolymer A-2! and the ethylene/α-olefin copolymer A-3! has aprominently narrow composition distribution. Moreover, because of lowstress within the high-shear region, the ethylene copolymer compositioncan be extruded at a high speed, and thus consumption of electric poweris small, resulting in economical advantage.

Films obtained from the fourth ethylene copolymer composition of theinvention are suitable for, for example, standard bags, heavy duty bags,wrapping films, materials for laminates, sugar bags, packaging bags foroily goods, packaging bags for moist goods, various packaging films suchas those for foods, bags for liquid transportation and agriculturalmaterials. The films may also be used as multi-layer films by laminatingthe films on various substrates such as a nylon substrate and apolyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.

Fifth ethylene copolymer composition!

The fifth ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer A-4! and ahigh-pressure radical polymerization low-density polyethylene B-4!.

Ethylene/α-olefin copolymer A-1!!

The ethylene/α-olefin copolymer A-4! used in the invention is a randomcopolymer of ethylene with an α-olefin of 3 to 20 carbon atoms. Examplesof the α-olefin of 3 to 20 carbon atoms employable for copolymerizationwith ethylene include propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene.

In the ethylene/α-olefin copolymer A-4!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, and constituent units derived from an α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

It is desired that the ethylene/α-olefin copolymer A-4! used in theinvention has the following properties (i) to (v).

(i) The density (d) is usually in the range of 0.880 to 0.960 g/cm³,preferably 0.890 to 0.935 g/cm³, more preferably 0.905 to 0.930 g/cm³.

(ii) The melt flow rate (MFR) is usually in the range of 0.01 to 200g/10 min, preferably 0.05 to 50 g/10 min, more preferably 0.1 to 10 g/10min.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

(iv) The melt tension (MT (g)) and the melt flow rate (MFR) satisfy therelation:

    MT≦2.2×MFR.sup.- 0.84.

(v) The fraction of a n-decane-soluble component at 23° C. (W % byweight) and the density (d) satisfy the relation:

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1,

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1.

It may be concluded from the relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the fraction (W) of a n-decane-soluble component andthe density (d), that the ethylene/α-olefin copolymer A-4! has a narrowcomposition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-4! is desirably not more than 0.5 per1,000 carbon atoms and less than 1.0 per one molecule of the copolymer.

In the ethylene/α-olefin copolymer A-4!, the B value represented by thefollowing formula: ##EQU1## (wherein PE is a molar fraction of theethylene component contained in the copolymer, Po is a molar fraction ofthe α-olefin component contained in the copolymer, and PoE is a molarfraction of the α-olefin/ethylene chain in all of the dyad chains),desirably is a number satisfying the following condition:

    1.00≦B,

    preferably 1.01≦B≦1.50,

    more preferably 1.01≦B≦1.30.

The B value indicates a distribution of each monomer component in thecopolymer chain, and can be calculated from the values for PE, Po andPoE defined above determined in accordance with the reports by, forexample, G. J. Ray (Macromolecules, 10, 773, 1977), J. C. Randall(Macromolecules, 15, 353, 1982), J. Polymer Science, Polymer PhysicsEd., 11, 275, 1973), and K. Kimura (Polymer, 25, 441, 1984). A copolymerwith a larger B value is a copolymer having a narrower compositiondistribution in which block-like chains of the copolymer chains arereduced and ethylene and α-olefin are uniformly distributed.

The B value indicating the composition distribution was calculated fromthe values for PE, Po and PoE which were obtained from a ¹³ C-NMRspectrum measured on a sample having been obtained by uniformlydissolving about 200 mg of a copolymer in 1 ml of hexachlorobutadieneunder the conditions of usually a temperature of 120° C., a frequency of25.05 MHz, a spectrum width of 1,500 Hz, a filter width of 1,500 Hz, apulse repetition period of 4.2 sec, a pulse width of 7 μsec andintegration times of 2,000 to 5,000.

The ethylene/α-olefin copolymer A-4! having the properties as mentionedabove can be prepared by copolymerizing ethylene and an α-olefin of 3 to20 carbon atoms in the presence of an olefin polymerization catalystformed from (a-3) a transition metal compound catalyst component and (b)an organoaluminum oxy-compound catalyst component, both being describedlater, in such a manner that the resulting copolymer would have adensity of 0.880 to 0.960 g/cm³. In particular, the copolymer can beprepared by copolymerizing ethylene and an α-olefin of 3 to 20 carbonatoms in the presence of an olefin polymerization catalyst (3) formedfrom (a-3) a transition metal compound catalyst component, (b) anorganoaluminum oxy-compound catalyst component, (c) a carrier, and ifnecessary, (d) an organoaluminum compound catalyst component, allcomponents being described later, or a prepolymerized catalyst (3) insuch a manner that the resulting copolymer would have a density of 0.880to 0.960 g/cm³.

First, the transition metal compound catalyst component (a-3) isexplained below.

The transition metal compound catalyst component (a-3) (sometimesreferred to as "component (a-3)" hereinafter) is a transition metalcompound represented by the following formula VI!

    ML.sub.X                                                    VI!

wherein M is a transition metal atom selected from Group IVB of theperiodic table, L is a ligand coordinating to the transition metal atomM, at least two of L are cyclopentadienyl groups, methylcyclopentadienylgroups, ethylcyclopentadientyl groups or substituted cyclopentadienylgroups having at least one substituent selected from hydrocarbon groupsof 3 to 10 carbon atoms, L other than the (substituted) cyclopentadienylgroup is a hydrocarbon group of 1 to 12 carbon atoms, an alkoxy group,an aryloxy group, a halogen atom, a trialkylsilyl group or a hydrogenatom, and x is a valence of the transition metal M.

In the above-mentioned formula VI!, M is a transition metal selectedfrom Group IVB of the periodic table, and concrete preferable examplesof M include zirconium, titanium and hafnium. Of these, particularlypreferred is zirconium.

The substituted cyclopentadienyl group may have two or more ofsubstituents, and each substituent may be the same or different. Whenthe substituted cyclopentadienyl has two or more of substituents, atleast one substituent is a hydrocarbon group of 3 to 10 carbon atoms,and other substituents are methyl, ethyl or a hydrocarbon group of 3 to10 carbon atoms. Further, each substituent coordinated to the M may bethe same or different.

The hydrocarbon group having 3 to 10 carbon atoms includes, for example,an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group,and concrete examples of these groups are

an alkyl group such as n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, t-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl;

a cycloalkyl group such as cyclopentyl and cyclohexyl;

an aryl group such as phenyl and tolyl; and

an aralkyl group such as benzyl and neophyl.

Of these, preferred is an alkyl group, and particularly preferred isn-propyl and n-butyl.

In the present invention, the (substituted) cyclopentadienyl groupcoordinated to the transition metal atom is preferably a substitutedcyclopentadienyl group, more preferably a cyclopentadienyl groupsubstituted with alkyl having 3 or more of carbon atoms, especially adi-substituted cyclopentadienyl group, particularly 1,3-substitutedcyclopentadienyl group.

In the above formula VI!, the ligand L coordinated to the transitionmetal atom M other than the (substituted) cyclopentadienyl groupincludes a hydrocarbon group of 1 to 12 carbon atoms, an alkoxy group,an aryloxy group, halogen, trialkylsilyl group or hydrogen.

The hydrocarbon group having 1 to 12 carbon atoms includes, for example,an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group,and concrete examples of these groups are as follows;

an alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, 2-ethylhexyl anddecyl;

a cycloalkyl group such as cyclopentyl and cyclohexyl;

an aryl group such as phenyl and tolyl;

an aralkyl group such as benzyl and neophyl;

an alkoxy group such as methoxy, ethoxy, n-propoxy, isopropoxy,n-butoxy, isobutoxy, sec-butoxy, t-butoxy, pentoxy, hexoxy and octoxy;

an aryloxy group such as phenoxy; and

halogen such as fluorine, chlorine, bromine and iodine;

a trialkylsilyl group such as trimethylsilyl, triethylsilyl andtriphenylsilyl.

Listed below are concrete examples of the transition metal compoundrepresented by the formula VI!.

Bis(cyclopentadienyl)zirconium dichloride,

Bis(methylcyclopentadienyl)zirconium dichloride,

Bis(ethylcyclopentadienyl)zirconium dichloride,

Bis(n-propylcyclopentadienyl)zirconium dichloride,

Bis(n-butylcyclopentadienyl)zirconium dichloride,

Bis(n-hexylcyclopentadienyl)zirconium dichloride,

Bis(methyl-n-propylcyclopentadienyl)zirconium dichloride,

Bis(methyl-n-butylcyclopentadienyl)zirconium dichloride,

Bis(dimethyl-n-butylcyclopentadienyl)zirconium dichloride,

Bis(n-butylcyclopentadienyl)zirconium dibromide,

Bis(n-butylcyclopentadienyl)zirconium methoxychloride,

Bis(n-butylcyclopentadienyl)zirconium ethoxychloride,

Bis(n-butylcyclopentadienyl)zirconium butoxychloride,

Bis(n-butylcyclopentadienyl)zirconium diethoxide,

Bis(n-butylcyclopentadienyl)zirconium methylchloride,

Bis(n-butylcyclopentadienyl)zirconium dimethyl,

Bis(n-butylcyclopentadienyl)zirconium benzylchloride,

Bis(n-butylcyclopentadienyl)zirconium dibenzyl,

Bis(n-butylcyclopentadienyl)zirconium phenylchloride, and

Bis(n-butylcyclopentadienyl)zirconium hydridechloride.

In the above exemplified compounds, di-substituted cyclopentadienylinclude 1,2- and 1,3-substituted, and tri-substituted include 1,2,3- and1,2,4-substituted.

There may also be used transition metal compounds obtained bysubstituting titanium or hafnium for zirconium in the above-exemplifiedzirconium compounds.

Of these transition metal compounds represented by the formula VI!,particularly preferred is

Bis(n-propylcyclopentadienyl)zirconium dichloride,

Bis(n-butylcyclopentadienyl)zirconium dichloride,

Bis(1-methyl-3-n-propylcyclopentadienyl)zirconium dichloride, or

Bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride.

The organoaluminum oxy-compound catalyst component (b) component (b)!which forms the olefin polymerization catalyst (3) is the same as theorganoluminum oxy-compound which forms the above mentioned olefinpolymerization catalyst (1).

The carrier (c) component (c)! which forms the olefin polymerizationcatalyst (3) is the same as the carrier which forms the above mentionedolefin polymerization catalyst (1).

The optionally used organoaluminum compound catalyst component (d)component (d)! is the same as the organoaluminum compound which formsthe above mentioned olefin polymerization catalyst (1).

The ethylene/α-olefin copolymer A-4! used in the present invention canbe prepared by the olefin polymerization catalyst (3) formed bycontacting the above-mentioned components (a-3), (b), (c) and ifnecessary, component (d). Though the mixing of these components (a-3),(b), (c) and (d) may be conducted in arbitrarily selected order, themixing and contacting is preferably conducted in the order of:

mixing and contacting the components (b) and (c), followed by mixing andcontacting the component (a-3), and if necessary, mixing and contactingthe component (d).

The mixing of the above-mentioned components (a-3), (b), (c) and (d) canbe carried out in an inert hydrocarbon.

As the inert hydrocarbon solvent, there may be mentioned an aliphatichydrocarbon, such as propane, butane, pentane, hexane, heptane, octane,decane, dodecane and kerosene;

an alicyclic hydrocarbon, such as cyclopentane, cyclohexane andmethylcyclopentane;

an aromatic hydrocarbon, such as benzene, toluene and xylene;

a halogenated hydrocarbon, such as ethylene chloride, chlorobenzene anddichloromethane; and a mixture thereof.

In the contacting and mixing of the components (a-3), (b), (c) and ifnecessary (d), the component (a-3) is used usually in an amount of5×10⁻⁶ to 5×10⁻⁴ mol, preferably 1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g ofthe component (c), and the concentration thereof is 1×10⁻⁴ to 2×10⁻²mol/l, preferably 2×10⁻⁴ to 1×10⁻² mol/l. The atomic ratio(Al/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-3) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5.

The components (a-3), (b) and (c), and if necessary, the component (d)are mixed and contacted at a temperature of usually -50° to 150° C.,preferably -20° to 120° C., with a contact time of 1 minute to 50 hours,preferably 10 minutes to 25 hours.

In the catalyst (3) for olefin polymerization obtained as describedabove, it is desirable that the transition metal derived from component(a-3) is supported in an amount of 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably1×10⁻⁵ to 2×10⁻⁴ g atom, and aluminum derived from components (b) and(d) is supported in an amount of 10⁻³ to 5×10⁻² g atom, preferably2×10⁻³ to 2×10⁻² g atom, all the amounts being based on 1 g of thecomponent (c).

Further, the catalyst for preparing the ethylene/α-olefin copolymer A-4!used in the present invention may be a prepolymerized catalyst (3)obtained by prepolymerization of olefin in the presence of theabove-mentioned components (a-3), (b) and (c), and if necessary, (d).

The prepolymerized catalyst (3) can be prepared by mixing the component(a-3), the component (b), the component (c), and if necessary, thecomponent (d), introducing olefin to the resulting mixture in the inerthydrocarbon solvent, and carrying out prepolymerization.

The olefins which can be prepolymerized include ethylene and α-olefinseach having 3 to 20 carbon atoms, for example, propylene, 1-butene,1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodeceneand 1-tetradecene. Of these, particularly preferred is ethylene or thecombination of ethylene and α-olefin used in the polymerization.

During the prepolymerization, the component (a-3) is used usually in aconcentration of is 1×10⁻⁶ to 2×10⁻² mol/l, preferably 5×10⁻⁵ to 1×10⁻²mol/l and amount thereof is usually 5×10⁻⁶ to 5×10⁻⁴ mol, preferably1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g of the component (c). The atomic ratio(A1/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-3) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5. Theprepolymerization is carried out at a temperature of -20° to 80° C.,preferably 0° to 60° C., with a time of 0.5 to 100 hours, preferably 1to 50 hours.

The prepolymerized catalyst (3) can be prepared as described below.First, the carrier (component (c)) is suspended in the inerthydrocarbon. To the suspension, the organoaluminum oxy-compound catalystcomponent (component (b)) is introduced, and reacted for predeterminedperiod. Successively, supernatant is removed, and the resulting solidcomponent is re-suspended in the inert hydrocarbon. Into the system, thetransition metal compound catalyst component (component (a-3)) is addedand reacted for predetermined period. Then, supernatant is removed toobtain a solid catalyst component. Continuously, the solid catalystcomponent obtained above is added into inert hydrocarbon containing theorganoaluminum compound catalyst component (component (d)), and olefinis introduced therein to obtain the prepolymerized catalyst (3).

An amount of prepolymerized polyolefin produced in the prepolymerizationis, desirably based on 1 g of the carrier (c), of 0.1 to 500 g,preferably 0.2 to 300 g, more preferably 0.5 to 200 g. In theprepolymerized catalyst (3), component (a-3) is desirably supported inan amount in terms of transition metal atom, based on 1 g of the carrier(c), of about 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably 1×10⁻⁵ to 2×10⁻⁴ gatom. Further, a molecular ratio (Al/M) of aluminum atom (Al) derivedfrom components (b) and (d) to transition metal atom (M) derived fromcomponent (a-3) is usually 5 to 200, preferably 10 to 150.

The prepolymerization may be carried out either batchwise orcontinuously, and under reduced pressure, normal pressure or appliedpressure. During the prepolymerization, hydrogen may be allowed to bepresent to obtain a prepolymer desirably having an intrinsic viscosityη! of 0.2 to 7 dl/g, preferably 0.5 to 5 dl/g as measured in decalin atleast 135° C.

The ethylene/α-olefin copolymers A-4! used in the present invention areobtained by copolymerizing ethylene with an α-olefin having 3 to 20carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene in the presence of the olefinpolymerization catalyst (3) or the prepolymerized catalyst (3).

Copolymerization of ethylene and α-olefin is carried out in a gas phaseor liquid phase, for example, in slurry. In the slurry polymerization,an inactive hydrocarbon or the olefin itself may be used as a solvent.

Concrete examples of the inactive hydrocarbon solvent include aliphatichydrocarbons such as butane, isobutane, pentane, hexane, octane, decane,dodecane, hexadecane and octadecane; alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and cyclooctane; aromatichydrocarbons such as benzene, toluene and xylene; and petroleumfractions such as gasoline, kerosene and gas oil. Of these inactivehydrocarbons, preferred are aliphatic hydrocarbons, alicyclichydrocarbons and petroleum fractions.

When the copolymerization is carried out by the slurry method or the gasphase method, the olefin polymerization catalyst (3) or theprepolymerized catalyst (3) is used at such amount that theconcentration of the transition metal compound becomes usually 10⁻⁸ to10⁻³ g atom/liter, preferably 10⁻⁷ to 10⁻⁴ g atom/liter in terms of thetransition metal in the polymerization reaction system.

Furthermore, in the polymerization, an organoaluminum oxy-compoundsimilar to the catalyst component (b) and/or an organoaluminum compound(d) may be added. In this case, the atomic ratio (Al/M) of the aluminumatom (Al) derived from the organoaluminum oxy-compound and theorganoaluminum compound to the transition metal atom (M) derived fromthe transition metal compound catalyst component (a-3) is 5 to 300,preferably 10 to 200, more preferably 15 to 150.

When the ethylene/α-olefin copolymer A-4! is prepared by the slurrypolymerization, the polymerization temperature is usually -50° to 100°C., preferably 0° to 90° C. When the ethylene/α-olefin copolymer A-4! isprepared by the gas phase polymerization, the polymerization temperatureis usually 0° to 120° C., preferably 20° to 100° C.

The polymerization is carried out usually at a normal pressure to 100kg/cm², preferably under a pressure condition of 2 to 50 kg/cm². Thepolymerization can be carried out either batchwise, semicontinuously orcontinuously.

Further, the polymerization may also be carried out in not less than 2steps having reaction conditions different from each other.

High-pressure radical polymerization low-density polyethylene B-4!π

The high-pressure radical polymerization low-density polyethylene B-4!used in the invention is a branched polyethylene having a number of longchain branches prepared by so-called high-pressure radicalpolymerization, and has a melt flow rate (MFR), as determined inaccordance with ASTM D1238-65T under the conditions of a temperature of190° C. and a load of 2.16 kg, of 0.1 to 50 g/10 min, preferably 0.2 to10 g/10 min, more preferably 0.2 to 8 g/10 min.

In the high-pressure radical polymerization low-density polyethyleneB-4! used in the invention, the index of the molecular weightdistribution (Mw/Mn, Mw=weight-average molecular weight,Mn=number-average molecular weight) measured by means of gel permeationchromatography (GPC) and the melt flow rate (MFR) satisfy the relation:

    7.5×log (MFR)-1.2≦Mw/Mn≦7.5×log (MFR)+12.5,

preferably

    7.5×log (MFR)-0.5≦Mw/Mn≦7.5×log (MFR)+12.0,

more preferably

    7.5×log (MFR)≦Mw/Mn≦7.5×log (MFR)+12.0.

The high-pressure radical polymerization low-density polyethylene B-4!used in the invention desirably has a density (d) of 0.910 to 0.930g/cm³.

Further, in the high-pressure radical polymerization low-densitypolyethylene B-4! used in the invention, a swell ratio indicating adegree of the long chain branch, namely, a ratio (Ds/D) of a diameter(Ds) of a strand to an inner diameter (D) of a nozzle, is desirably notless than 1.3. The strand used herein is a strand extruded from a nozzlehaving an inner diameter (D) of 2.0 mm and a length of 15 mm at anextrusion rate of 10 mm/min and a temperature of 190° C. using acapillary type flow property tester.

The high-pressure radical polymerization low-density polyethylene B-4!as mentioned above may be a copolymer obtained by copolymerizingethylene with a polymerizable monomer such as other α-olefin, vinylacetate or acrylic ester, provided that the object of the presentinvention is not marred.

Ethylene copolymer composition!

The fifth ethylene copolymer composition according to the inventioncomprises the aforementioned ethylene/α-olefin copolymer A-4! and thehigh-pressure radical polymerization low-density polyethylene B-4!, anda weight ratio ( A-4!: B-4!) between the ethylene/α-olefin copolymerA-4! and the high-pressure radical polymerization low-densitypolyethylene B-4! is usually in the range of 99:1 to 60:40, preferably98:2 to 70:30, more preferably 98:2 to 80:20.

When the amount of the high-pressure radical polymerization low-densitypolyethylene B-4! is less than the lower limit of the above range, theresulting composition is sometimes improved insufficiently in thetransparency and the melt tension, and when the amount thereof is largerthan the upper limit of the above range, the resulting composition issometimes markedly deteriorated in the tensile strength and the stresscrack resistance.

The fifth ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The fifth ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-4!, the high-pressure radical polymerization low-density polyethyleneB-4!, and if necessary, other optional components by the use of anextruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-4!, the high-pressure radical polymerization low-density polyethyleneB-4!, and if necessary, other optional components in an appropriate goodsolvent (e.g., hydrocarbon solvent such as hexane, heptane, decane,cyclohexane, benzene, toluene and xylene), and then removing the solventfrom the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-4!, the high-pressure radical polymerization low-densitypolyethylene B-4!, and if necessary, other optional components in anappropriate good solvent to prepare solutions, then mixing thesolutions, and removing the solvent from the resulting mixture.

(4) A process of combining the above processes (1) to (3).

The fifth ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is excellent in transparency andmechanical strength, and has properties inherently belonging to generalLLDPE, such as heat-sealing properties, hot-tack properties, heatresistance and blocking resistance. Further, the film is free fromsurface stickiness because the ethylene/α-olefin copolymer A-4! has aprominently narrow composition distribution. Moreover, because of lowstress within the high-shear region, the ethylene copolymer compositioncan be extruded at a high speed, and consumption of electric power issmall, resulting in economical advantage.

Films obtained by processing the fifth ethylene copolymer composition ofthe present invention are suitable for, for example, standard bags,heavy bags, wrapping films, materials for laminates, sugar bags,packaging bags for oily goods, packaging bags for moist goods, variouspackaging films such as those for foods, bags for liquid transportationand agricultural materials. The films may also be used as multi-layerfilms by laminating the films on various substrates such as a nylonsubstrate and a polyester substrate. Further, the films may be used forliquid transportation bags obtained by blow molding, bottles obtained byblow molding, tubes and pipes obtained by extrusion molding, pull-offcaps, injection molded products such as daily use miscellaneous goods,fibers and large-sized molded articles obtained by rotational molding.

Sixth ethylene copolymer composition!

The sixth ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer A-4! and acrystalline polyolefin B-2!.

Ethylene/α-olefin copolymer A-4!!

The ethylene/α-olefin copolymer A-4! employable for the sixth ethylenecopolymer composition is the same as the ethylene/α-olefin copolymerused for the fifth ethylene copolymer composition described above.

Crystalline polyolefin B-2!!

The crystalline polyolefin B-2! employable for the sixth ethylenecopolymer composition is the same as the crystalline polyolefins (B-I)to (B-III) used for the second ethylene copolymer composition describedbefore.

Ethylene copolymer composition!

The sixth ethylene copolymer composition according to the inventioncomprises the ethylene/α-olefin copolymer A-4! and the crystallinepolyolefin B-2!, and a weight ratio ( A-4!: B-2!) between theethylene/α-olefin copolymer A-4! and the crystalline polyolefin B-2! isusually in the range of 99:1 to 60:40, preferably 98:2 to 70:30, morepreferably 98:2 to 80:20.

The sixth ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The sixth ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-4!, the crystalline polyolefin B-2!, and if necessary, other optionalcomponents by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-4!, the crystalline polyolefin B-2!, and if necessary, other optionalcomponents in an appropriate good solvent (e.g., hydrocarbon solventsuch as hexane, heptane, decane, cyclohexane, benzene, toluene andxylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-4!, the crystalline polyolefin B-2!, and if necessary, otheroptional components in an appropriate good solvent to prepare solutions,then mixing the solutions, and removing the solvent from the resultingmixture.

(4) A process of combining the above processes (1) to (3).

The sixth ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is well-balanced between thetransparency and the rigidity, and has properties inherently belongingto general LLDPE, such as heat-sealing properties, hot-tack propertiesand heat resistance. Further, the film is free from surface stickinessbecause the ethylene/α-olefin copolymer A-4! has a prominently narrowcomposition distribution.

Films obtained by processing the sixth ethylene copolymer composition ofthe invention are suitable for, for example, standard bags, heavy bags,wrapping films, materials for laminates, sugar bags, packaging bags foroily goods, packaging bags for moist goods, various packaging films suchas those for foods, bags for liquid transportation and agriculturalmaterials. The films may also be used as multi-layer films by laminatingthe films on various substrates such as a nylon substrate and apolyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.Particularly, the films are most suitable for liquid transportationbags.

Seventh ethylene copolymer composition!

The seventh ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer A-4! and an olefintype elastomer B-3!.

Ethylene/α-olefin copolymer A-4!!

The ethylene/α-olefin copolymer A-4! employable for the seventh ethylenecopolymer composition is the same as the ethylene/α-olefin copolymerused for the fifth ethylene copolymer composition described before.

Olefin type elastomer B-3!!

The olefin type elastomer B-3! employable for the seventh ethylenecopolymer composition is the same as the olefin type elastomer used forthe third ethylene copolymer composition described before.

Ethylene copolymer composition!

The seventh ethylene copolymer composition according to the inventioncomprises the ethylene/α-olefin copolymer A-4! and the olefin typeelastomer B-3!, and a weight ratio ( A-4!: B-3!) between theethylene/α-olefin copolymer A-4! and the olefin type elastomer B-3! isusually in the range of 99:1 to 60:40, preferably 95:5 to 70:30, morepreferably 98:2 to 80:20. The ethylene/α-olefin copolymer A-4! and theolefin type elastomer B-3! are appropriately selected so that a densityratio ( B-3!/ A-4!) of the olefin type elastomer B-3! to theethylene/α-olefin copolymer A-4! is less than 1, preferably in the rangeof 0.905 to 0.980.

The seventh ethylene copolymer composition according to the inventionmay contain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, antifogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The seventh ethylene copolymer composition according to the inventioncan be prepared by known processes, for example, processes describedbelow.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-4!, the olefin type elastomer B-3!, and if necessary, other optionalcomponents by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-4!, the olefin type elastomer B-3!, and if necessary, other optionalcomponents in an appropriate good solvent (e.g., hydrocarbon solventsuch as hexane, heptane, decane, cyclohexane, benzene, toluene andxylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-4!, the olefin type elastomer B-3!, and if necessary, otheroptional components in an appropriate good solvent to prepare solutions,then mixing the solutions, and removing the solvent from the resultingmixture.

(4) A process of combining the above processes (1) to (3).

The seventh ethylene copolymer composition according to the presentinvention is subjected to ordinary air-cooling inflation molding,two-stage air-cooling inflation molding, high-speed inflation molding,T-die film molding, water-cooling inflation molding or the like, toobtain a film. The film thus obtained is well-balanced between thetransparency and the rigidity, and has properties inherently belongingto general LLDPE, such as heat-sealing properties, hot-tack propertiesand heat resistance. Further, the film is free from surface stickinessbecause the ethylene/α-olefin copolymer A-4! has a prominently narrowcomposition distribution.

Films obtained by processing the seventh ethylene copolymer compositionof the invention are suitable for, for example, standard bags, heavybags, wrapping films, materials for laminates, sugar bags, packagingbags for oily goods, packaging bags for moist goods, various packagingfilms such as those for foods, bags for liquid transportation andagricultural materials. The films may also be used as multi-layer filmsby laminating the films on various substrates such as a nylon substrateand a polyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibers,and large-sized molded articles obtained by rotational molding.Particularly, the films are most suitable as wrapping films.

Eighth ethylene copolymer composition!

The eighth ethylene copolymer composition according to the presentinvention comprises an ethylene/α-olefin copolymer composition Ib! whichcomprises an ethylene/α-olefin copolymer A-5! and an ethylene/α-olefincopolymer A-6!, and a high-pressure radical polymerization low-densitypolyethylene IIb!.

Ethylene/α-olefin copolymer A-5!!

The ethylene/α-olefin copolymer A-5! for forming the eighth ethylenecopolymer composition of the invention is a random copolymer of ethylenewith an α-olefin of 3 to 20 carbon atoms. Examples of the α-olefin of 3to 20 carbon atoms employable for copolymerization with ethylene includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and1-eicosene.

In the ethylene/α-olefin copolymer A-5!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, and constituent units derived from α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

The ethylene/α-olefin copolymer A-5! has the following properties (i) to(v).

(i) The density (d) is usually in the range of 0.880 to 0.940 g/cm³,preferably 0.890 to 0.935 g/cm³, more preferably 0.900 to 0.930 g/cm³.

(ii) The intrinsic viscosity η_(A-5) ! as measured in decalin at 135° C.is in the range of 1.0 to 10.0 dl/g, preferably 1.25 to 8 dl/g, morepreferably 1.27 to 6 dl/g.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

(iv) The melt tension (MT (g)) and the melt flow rate (MFR) satisfy therelation:

    MT≦2.2×MFR.sup.-0.84.

(v) The fraction of a n-decane-soluble component (W % by weight) at roomtemperature and the density (d) satisfy the relation:

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1.

It may be concluded from the relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the fraction (W) of a n-decane-soluble component andthe density (d), that the ethylene/α-olefin copolymer A-5! has a narrowcomposition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-5! desirably is not more than 0.5 per1,000 carbon atoms and less than 1 per one molecule of the copolymer.

The ethylene/α-olefin copolymer A-5! having the properties as mentionedabove can be prepared by copolymerizing ethylene with an α-olefin of 3to 20 carbon atoms in the presence of the aforementioned olefinpolymerization catalyst (3) or prepolymerized catalyst (3) under thesame conditions as those for preparing the ethylene/α-olefin copolymerA-5! in such a manner that the resulting copolymer would have a densityof 0.880 to 0.940 g/cm³.

When a slurry polymerization process is used for preparing theethylene/α-olefin copolymer A-5!, the polymerization temperature isusually in the range of -50° to 90° C., preferably 0° to 80° C., andwhen a gas phase polymerization process is used therefor, thepolymerization temperature is usually in the range of 0° to 90° C.,preferably 20° to 80° C.

Ethylene/α-olefin copolymer A-6!!

The ethylene/α-olefin copolymer A-6! for forming the eighth ethylenecopolymer composition of the invention is a random copolymer of ethylenewith an α-olefin of 3 to 20 carbon atoms. Examples of the α-olefin of 3to 20 carbon atoms employable for copolymerization with ethylene includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and1-eicosene.

In the ethylene/α-olefin copolymer A-6!, it is desired that constituentunits derived from ethylene are present in an amount of 55 to 99% byweight, preferably 65 to 98% by weight, more preferably 70 to 96% byweight, and constituent units derived from α-olefin of 3 to 20 carbonatoms are present in an amount of 1 to 45% by weight, preferably 2 to35% by weight, more preferably 4 to 30% by weight.

The ethylene/α-olefin copolymer A-6! has the following properties (i) to(v).

(i) The density (d) is usually in the range of 0.910 to 0.960 g/cm³,preferably 0.915 to 0.955 g/cm³, more preferably 0.920 to 0.950 g/cm³.

(ii) The intrinsic viscosity η_(A-6) ! as measured in decalin at 135° C.is in the range of 0.5 to 2.0 dl/g, preferably 0.55 to 1.9 dl/g, morepreferably 0.6 to 1.8 dl/g.

(iii) The temperature (Tm (°C.)) at which the endothermic curve of thecopolymer measured by a differential scanning calorimeter (DSC) showsthe maximum peak and the density (d) satisfy the relation:

    Tm<400×d-250,

    preferably Tm<450×d-297,

    more preferably Tm<500×d-344,

    particularly preferably Tm<550×d-391.

(iv) The melt tension (MT (g)) and the melt flow rate (MFR) satisfy therelation:

    MT≦2.2×MFR.sup.-0.84.

(v) The quantity fraction (W (% by weight)) of a n-decane-solublecomponent at room temperature and the density (d) satisfy the relation:

in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1,

    preferably W<60×exp (-100(d-0.88))+0.1,

    more preferably W<40×exp (-100(d-0.88))+0.1,

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1.

It may be concluded from the relation between the temperature (Tm) atwhich the endothermic curve measured by a differential scanningcalorimeter (DSC) shows the maximum peak and the density (d), and therelation between the fraction (W) of a n-decane-soluble component andthe density (d), that the ethylene/α-olefin copolymer A-6! has a narrowcomposition distribution.

Further, the number of unsaturated bond present in the molecule of theethylene/α-olefin copolymer A-6! desirably is not more than 0.5 per1,000 carbon atoms and less than 1 per one molecule of the copolymer.

The ethylene/α-olefin copolymer A-6! having the properties as mentionedabove can be prepared by copolymerizing ethylene with an α-olefin of 3to 20 carbon atoms in the presence of an olefin polymerization catalyst(4) or a prepolymerized catalyst (4) formed from (a-4) a transitionmetal compound catalyst component, (b) an organoaluminum oxy-compoundcatalyst component, (c) a carrier, and if necessary, (d) anorganoaluminum compound catalyst component, all components beingdescribed later, in such a manner that the resulting copolymer wouldhave a density of 0.910 to 0.960 g/cm³.

First, the transition metal compound catalyst component (a-4) isexplained below.

The transition metal compound catalyst component (a-4) (sometimesreferred to as "component (a-4)" hereinafter) is a compound of atransition metal in Group IV of the periodic table which contains aligand having a cyclopentadienyl skeleton. There is no specificlimitation on the component (a-4), as far as it is a compound of atransition metal in Group IV of the periodic table which contains aligand having a cyclopentadienyl skeleton. However, the component (a-4)preferably is a transition metal compound represented by the followingformula VII!.

    ML.sub.X                                                    VII!

wherein M is a transition metal atom selected from Group IVB of theperiodic table, L is a ligand coordinating to the transition metal, atleast one of L is a ligand having a cyclopentadienyl skeleton, L otherthan the ligand having a cyclopentadienyl skeleton is a hydrocarbongroup of 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, atrialkylsilyl group, a SO₃ R group (R is a hydrocarbon group of 1 to 8carbon atoms which may have a substituent group such as halogen), ahalogen atom or a hydrogen atom, and X is a valance of the transitionmetal.

The transition metal compound represented by the above formula VII!includes the transition metal compound represented by the formula VI!which is cited before as the transition metal catalyst component (a-3).

In the above-mentioned formula VII!, M is a transition metal selectedfrom Group IVB of the periodic table, and concrete preferable examplesof M include zirconium, titanium and hafnium. Of these, particularlypreferred is zirconium.

The ligands having a cyclopentadienyl skeleton include, for example,cyclopentadienyl; an alkyl-substituted cyclopentadienyl group such asmethylcyclopentadienyl, dimethylcyclopentadienyl,trimethylcyclopentadienyl, tetramethylcyclopentadienyl,pentamethylcyclopentadienyl, ethylcyclopentadienyl,methylethylcyclopentadienyl, propylcyclopentadienyl,methylpropylcyclopentadienyl, butylcyclopentadienyl,methylbutylcyclopentadienyl and hexylcyclopentadienyl; indenyl,4,5,6,7-tetrahydroindenyl and fluorenyl. These groups may be substitutedwith halogen atom or trialkylsilyl group, and the like.

Of these ligands coordinated to the transition metal, particularlypreferred is the alkyl-substituted cyclopentadienyl group.

When the compound represented by the above formula VII! contains two ormore of the groups having a cyclopentadienyl skeleton, two of them eachhaving a cyclopentadienyl skeleton can be bonded together through analkylene group (e.g., ethylene and propylene), a substituted alkylenegroup such as isopropylidene and diphenylmethylene, a silylene group, ora substituted silylene group such as dimethylsilylene, diphenylsilyleneand methylphenylsilylene.

Concrete examples of the ligand L other than those having acyclopentadienyl skeleton are as follows:

The hydrocarbon group having 1 to 12 carbon atoms includes, for example,an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group,and concrete examples of these groups are as follows;

an alkyl group such as methyl, ethyl, propyl, isopropyl and butyl;

a cycloalkyl group such as cyclopentyl and cyclohexyl;

an aryl group such as phenyl and tolyl;

an aralkyl group such as benzyl and neophyl;

an alkoxy group such as methoxy, ethoxy and butoxy;

an aryloxy group such as phenoxy; and halogen such as fluorine,chlorine, bromine and iodine.

The ligand represented by SO₃ R includes, for example,p-toluenesulfonate, methanesulfonate and trifluoromethanesulfonate.

Such a metallocene compound containing ligands each having acyclopentadienyl skeleton (e.g. having a transition metal with a valenceof 4) may be represented more concretely by the formula VII'!

    R.sup.2 kR.sup.3 lR.sup.4 mR.sup.5 nM                       VII'!

wherein M is a transition metal as mentioned above, R² is a group havinga cyclopentadienyl skeleton (ligand), R³, R⁴ and R⁵ are each a grouphaving a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group,an aryl group, an aralkyl group, an alkoxy group, an aryloxy group,trialkylsilyl group, SO₃ R group, halogen or hydrogen, k is an integerof not less than 1, and k+l+m+n=4.

As the component (a-4), preferred is the metallocene compoundrepresented by the above formula VII'! in which at least two of R², R³,R⁴ and R⁵, that is, R² and R³ are each a group having a cyclopentadienylskeleton (ligand). Said groups having a cyclopentadienyl skeleton may bebonded together through a group such as an alkylene group (e.g.,ethylene and propylene), a substituted alkylene group such asisopropylidene and diphenylmethylene, a silylene group, and asubstituted silylene group such as dimethylsilylene, diphenylsilyleneand methylphenylsilylene. Further, R⁴ and R⁵ are each a group having acyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, an alkoxy group, an aryloxy group,trialkylsilyl group, SO₃ R group, halogen or hydrogen.

Listed below are concrete examples of the transition metal compoundhaving zirconium as M.

Bis(indenyl)zirconium dichloride,

Bis(indenyl)zirconium dibromide,

Bis(indenyl)zirconium bis(p-toluenesulfonate),

Bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Bis(fluorenyl)zirconium dichloride,

Ethylenebis(indenyl)zirconium dichloride,

Ethylenebis(indenyl)zirconium dibromide,

Ethylenebis(indenyl)dimethylzirconium,

Ethylenebis(indenyl)diphenylzirconium,

Ethylenebis(indenyl)methylzirconium monochloride,

Ethylenebis(indenyl)zirconium bis(methanesulfonate),

Ethylenebis(indenyl)zirconium bis(p-toluenesulfonate),

Ethylenebis(indenyl)zirconium bis(trifluoromethanesulfonate),

Ethylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Isopropylidene(cyclopentadienylfluorenyl)zirconium dichloride,

Isopropylidene(cyclopentadienyl-methylcyclopentadienyl)zirconiumdichloride,

Dimethylsilylenebis(cyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(methylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(dimethylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(trimethylcyclopentadienyl)zirconium dichloride,

Dimethylsilylenebis(indenyl)zirconium dichloride,

Dimethylsilylenebis(indenyl)zirconium bis(trifluoromethanesulfonate),

Dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride,

Dimethylsilylenebis(cyclopentadienyl-fluorenyl)zirconium dichloride,

Diphenylsilylenebis(indenyl)zirconium dichloride,

Methylphenylsilylenebis(indenyl)zirconium dichloride,

Bis(cyclopentadienyl)zirconium dichloride,

Bis(cyclopentadienyl)zirconium dibromide,

Bis(cyclopentadienyl)methylzirconium monochloride,

Bis(cyclopentadienyl)ethylzirconium monochloride,

Bis(cyclopentadienyl)cyclohexylzirconium monochloride,

Bis(cyclopentadienyl)phenylzirconium monochloride,

Bis(cyclopentadienyl)benzylzirconium monochloride,

Bis(cyclopentadienyl)zirconium monochloride monohydride,

Bis(cyclopentadienyl)methylzirconium monohydride,

Bis(cyclopentadienyl)dimethylzirconium,

Bis(cyclopentadienyl)diphenylzirconium,

Bis(cyclopentadienyl)dibenzylzirconium,

Bis(cyclopentadienyl)zirconium methoxychloride,

Bis(cyclopentadienyl)zirconium ethoxychloride,

Bis(cyclopentadienyl)zirconium bis(methanesulfonate),

Bis(cyclopentadienyl)zirconium bis(p-toluenesulfonate),

Bis(cyclopentadienyl)zirconium bis(trifluoromethanesulfonate),

Bis(methylcyclopentadienyl)zirconium dichloride,

Bis(dimethylcyclopentadienyl)zirconium dichloride,

Bis(dimethylcyclopentadienyl)zirconium ethoxychloride,

Bis(dimethylcyclopentadienyl)zirconium bis(trifluoromethanesulfonate),

Bis(ethylcyclopentadienyl)zirconium dichloride,

Bis(methylethylcyclopentadienyl)zirconium dichloride,

Bis(propylcyclopentadienyl)zirconium dichloride,

Bis(methylpropylcyclopentadienyl)zirconium dichloride,

Bis(butylcyclopentadienyl)zirconium dichloride,

Bis(methylbutylcyclopentadienyl)zirconium dichloride,

Bis(methylbutylcyclopentadienyl)zirconium bis(methanesulfonate),

Bis(trimethylcyclopentadienyl)zirconium dichloride,

Bis(tetramethylcyclopentadienyl)zirconium dichloride,

Bis(pentamethylcyclopentadienyl)zirconium dichloride,

Bis(hexylcyclopentadienyl)zirconium dichloride, and

Bis(trimethylsilylcyclopentadienyl)zirconium dichloride.

In the above exemplified compounds, di-substituted cyclopentadienylincludes 1,2- and 1,3-substituted, and tri-substituted includes 1,2,3-and 1,2,4-substituted. Further, the alkyl group such as propyl or butylincludes n-, i-, sec- and tert- isomers.

There may also be used transition metal compounds obtained bysubstituting titanium or hafnium for zirconium in the above-exemplifiedzirconium compounds.

The above listed compounds and the transition metal compoundsrepresented by the above formula VI! are used as transition metalcatalyst component (a-4). Preferred are the above mentioned transitionmetal compounds represented by the formula VI!. Of these, particularlypreferred is

Bis(n-propylcyclopentadienyl)zirconium dichloride,

Bis(n-butylcyclopentadienyl)zirconium dichloride,

Bis(1-methyl-3-n-propylcyclopentadienyl)zirconium dichloride, or

Bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride.

Further, the transition metal catalyst component (a-3) used in thepreparation of the ethylene/α-olefin copolymer A-5! and the transitionmetal catalyst component (a-4) used in the preparation of theethylene/α-olefin copolymer A-6! are preferably the same compounds.

The organoaluminum oxy-compound catalyst component (b) component (b)!which forms the olefin polymerization catalyst (4) is the same as theorganoluminum oxy-compound which forms the above mentioned olefinpolymerization catalyst (1).

The carrier (c) component (c)! which forms the olefin polymerizationcatalyst (4) is the same as the carrier which forms the above mentionedolefin polymerization catalyst (1).

The optionally used organoaluminum compound catalyst component (d)component (d)! is the same as the organoaluminum compound which formsthe above mentioned olefin polymerization catalyst (1).

The ethylene/α-olefin copolymer A-6! used in the present invention canbe prepared by the olefin polymerization catalyst (4) formed bycontacting the above-mentioned components (a-4), (b), (c) and ifnecessary, component (d). Though the mixing of these components (a-4),(b), (c) and (d) may be conducted in arbitrarily selected order, themixing and contacting is preferably conducted in the order of:

mixing and contacting the components (b) and (c), followed by mixing andcontacting the component (a-4), and if necessary, mixing and contactingthe component (d).

The mixing of the above-mentioned components (a-4), (b), (c) and (d) canbe carried out in an inert hydrocarbon.

As the inert hydrocarbon solvent, there may be mentioned an aliphatichydrocarbon, such as propane, butane, pentane, hexane, heptane, octane,decane, dodecane and kerosene;

an alicyclic hydrocarbon, such as cyclopentane, cyclohexane andmethylcyclopentane;

an aromatic hydrocarbon, such as benzene, toluene and xylene;

a halogenated hydrocarbon, such as ethylene chloride, chlorobenzene anddichloromethane; and a mixture thereof.

In the contacting and mixing of the components (a-4), (b), (c) and ifnecessary (d), the component (a-4) is used usually in an amount of5×10⁻⁶ to 5×10⁻⁴ mol, preferably 1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g ofthe component (c), and the concentration thereof is 1×10⁻⁴ to 2×10⁻²mol/l, preferably 2×10⁻⁴ to 1×10⁻² mol/l. The atomic ratio(Al/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-4) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5.

The components (a-4), (b) and (c), and if necessary, the component (d)are mixed and contacted at a temperature of usually -50° to 150° C.,preferably -20° to 120° C., with a contact time of 1 minute to 50 hours,preferably 10 minutes to 25 hours.

In the catalyst (4) for olefin polymerization obtained as describedabove, it is desirable that the transition metal derived from component(a-4) is supported in an amount of 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably1×10⁻⁵ to 2×10⁻⁴ g atom, and aluminum derived from components (b) and(d) is supported in an amount of 10⁻³ to 5×10⁻² g atom, preferably2×10⁻³ to 2×10⁻² g atom, all the amounts being based on 1 g of thecomponent (c).

Further, the catalyst for preparing the ethylene/α-olefin copolymer A-6!used in the present invention may be a prepolymerized catalyst (4)obtained by prepolymerization of olefin in the presence of theabove-mentioned components (a-4), (b) and (c), and if necessary, (d).

The prepolymerized catalyst (4) can be prepared by mixing the component(a-4), the component (b), the component (c), and if necessary, thecomponent (d), introducing olefin to the resulting mixture in the inerthydrocarbon solvent, and carrying out prepolymerization.

The olefins which can be prepolymerized include ethylene and α-olefinseach having 3 to 20 carbon atoms, for example, propylene, 1-butene,1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodeceneand 1-tetradecene. Of these, particularly preferred is ethylene or thecombination of ethylene and α-olefin used in the polymerization.

During the prepolymerization, the component (a-4) is used usually in aconcentration of is 1×10⁻⁶ to 2×10⁻² mol/l, preferably 5×10⁻⁵ to 1×10⁻²mol/l and amount thereof is usually 5×10⁻⁶ to 5×10⁻⁴ mol, preferably1×10⁻⁵ to 2×10⁻⁴ mol based on 1 g of the component (c). The atomic ratio(Al/transition metal) of the aluminum in the component (b) to thetransition metal in the component (a-4) is usually 10 to 500, preferably20 to 200. The atomic ratio (Al-d/Al-b) of the aluminum atoms (Al-d) inthe component (d) optionally used to the aluminum atoms (Al-b) in thecomponent (b) is usually 0.02 to 3, preferably 0.05 to 1.5. Theprepolymerization is carried out at a temperature of -20° to 80° C.,preferably 0° to 60° C., with a time of 0.5 to 100 hours, preferably 1to 50 hours.

The prepolymerized catalyst (4) can be prepared as described below.First, the carrier (component (c)) is suspended in the inerthydrocarbon. To the suspension, the organoaluminum oxy-compound catalystcomponent (component (b)) is introduced, and reacted for predeterminedperiod. Successively, supernatant is removed, and the resulting solidcomponent is re-suspended in the inert hydrocarbon. Into the system, thetransition metal compound catalyst component (component (a-4)) is addedand reacted for predetermined period. Then, supernatant is removed toobtain a solid catalyst component. Continuously, the solid catalystcomponent obtained above is added into inert hydrocarbon containing theorganoaluminum compound catalyst component (component (d)), and olefinis introduced therein to obtain the prepolymerized catalyst (4).

An amount of prepolymerized polyolefin produced in the prepolymerizationis, desirably based on 1 g of the carrier (c), of 0.1 to 500 g,preferably 0.2 to 300 g, more preferably 0.5 to 200 g. In theprepolymerized catalyst (4), component (a-4) is desirably supported inan amount in terms of transition metal atom, based on 1 g of the carrier(c), of about 5×10⁻⁶ to 5×10⁻⁴ g atom, preferably 1×10⁻⁵ to 2×10⁻⁴ gatom. Further, a molecular ratio (Al/M) of aluminum atom (Al) derivedfrom components (b) and (d) to transition metal atom (M) derived fromcomponent (a-4) is usually 5 to 200, preferably 10 to 150.

The prepolymerization may be carried out either batchwise orcontinuously, and under reduced pressure, normal pressure or appliedpressure. During the prepolymerization, hydrogen may be allowed to bepresent to obtain a prepolymer desirably having an intrinsic viscosityη! of 0.2 to 7 dl/g, preferably 0.5 to 5 dl/g as measured in decalin atleast 135° C.

The ethylene/α-olefin copolymers A-6! used in the present invention areobtained by copolymerizing ethylene with an α-olefin having 3 to 20carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene in the presence of the olefinpolymerization catalyst (4) or the prepolymerized catalyst (4).

Copolymerization of ethylene and α-olefin is carried out in a gas phaseor liquid phase, for example, in slurry. In the slurry polymerization,an inactive hydrocarbon or the olefin itself may be used as a solvent.

Concrete examples of the inactive hydrocarbon solvent include aliphatichydrocarbons such as butane, isobutane, pentane, hexane, octane, decane,dodecane, hexadecane and octadecane; alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and cyclooctane; aromatichydrocarbons such as benzene, toluene and xylene; and petroleumfractions such as gasoline, kerosene and gas oil. Of these inactivehydrocarbons, preferred are aliphatic hydrocarbons, alicyclichydrocarbons and petroleum fractions.

When the copolymerization is carried out by the slurry method or the gasphase method, the olefin polymerization catalyst (4) or theprepolymerized catalyst (4) is used at such amount that theconcentration of the transition metal compound becomes usually 10⁻⁸ to10⁻³ g atom/liter, preferably 10⁻⁷ to 10⁻⁴ g atom/liter in terms of thetransition metal in the polymerization reaction system.

Furthermore, in the polymerization, an organoaluminum oxy-compoundsimilar to the catalyst component (b) and/or an organoaluminum compound(d) may be added. In this case, the atomic ratio (Al/M) of the aluminumatom (Al) derived from the organoaluminum oxy-compound and theorganoaluminum compound to the transition metal atom (M) derived fromthe transition metal catalyst component (a-4) is 5 to 300, preferably 10to 200, more preferably 15 to 150.

When the ethylene/α-olefin copolymer A-6! is prepared by the slurrypolymerization, the polymerization temperature is usually -30° to 100°C., preferably 20° to 90° C. When the ethylene/α-olefin copolymer A-6!is prepared by the gas phase polymerization, the polymerizationtemperature is usually 20° to 120° C., preferably 40° to 100° C.

The polymerization is carried out usually at a normal pressure to 100kg/cm², preferably under a pressure condition of 2 to 50 kg/cm². Thepolymerization can be carried out either batchwise, semicontinuously orcontinuously.

Ethylene/α-olefin copolymer composition Ib!!

The ethylene/α-olefin copolymer composition Ib! comprises theethylene/α-olefin copolymer A-5! and the ethylene/α-olefin copolymerA-6!. In this composition Ib!, the ethylene/α-olefin copolymer A-5! iscontained in an amount of 5 to 95% by weight, preferably 10 to 95% byweight, and the ethylene/α-olefin copolymer A-6! is contained in anamount of 5 to 95% by weight, preferably 10 to 90% by weight.

The ethylene/α-olefin copolymer A-5! and the ethylene/α-olefin copolymerA-6! are appropriately combined so that a density ratio ( A-5!/ A-6!) ofthe ethylene/α-olefin copolymer A-5! to the ethylene/α-olefin copolymerA-6! is less than 1, preferably in the range of 0.930 to 0.999. Further,they also are appropriately combined so that a ratio ( η_(A-5) !/η_(A-6) !) of the intrinsic viscosity η_(A-5) ! of the ethylene/α-olefincopolymer A-5! to the intrinsic viscosity η_(A-6) ! of theethylene/α-olefin copolymer A-6! is not less than 1, preferably in therange of 1.05 to 10, more preferably 1.1 to 5.

The ethylene/α-olefin copolymer composition has a density of usually0.890 to 0.955 g/cm³, preferably 0.900 to 0.950 g/cm³, and has a meltflow rate (MFR), as determined in accordance with ASTM D1238-65T underthe conditions of a temperature of 190° C. and a load of 2.16 kg, of 0.1to 100 g/10 min, preferably 0.2 to 50 g/10 min.

The ethylene/α-olefin copolymer composition Ib! can be prepared by knownprocesses, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymerA-5!, the ethylene/α-olefin copolymer A-6!, and if necessary, otheroptional components by the use of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymerA-5!, the ethylene/α-olefin copolymer A-6!, and if necessary, otheroptional components in an appropriate good solvent (e.g., hydrocarbonsolvent such as hexane, heptane, decane, cyclohexane, benzene, tolueneand xylene), and then removing the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer A-5!, the ethylene/α-olefin copolymer A-6!, and if necessary,other optional components in an appropriate good solvent to preparesolutions, then mixing the solutions, and removing the solvent from theresulting mixture.

(4) A process in any combination of the above processes (1) to (3).

Further, the ethylene/α-olefin copolymer composition Ib! may be preparedby forming the ethylene/α-olefin copolymer A-5! and theethylene/α-olefin copolymer A-6!in two or more copolymerization stageshaving reaction conditions different from each other, or may be preparedby separately forming the ethylene/α-olefin copolymer A-5! and theethylene/α-olefin copolymer A-6! by the use of plural polymerizers.

High-pressure radical polymerization low-density polyethylene IIb!!

The high-pressure radical polymerization low-density polyethylene IIb!employable for the eighth ethylene copolymer composition is the same asthe high-pressure radical polymerization low-density polyethylene B-4!used for the fifth ethylene copolymer composition described before.

Ethylene copolymer composition!

The eighth ethylene copolymer composition according to the inventioncomprises the ethylene/α-olefin copolymer composition Ib! and thehigh-pressure radical polymerization low-density polyethylene IIb!. Itis desirable that a weight ratio ( Ib!: IIb!) between theethylene/α-olefin copolymer composition Ib! and the high-pressureradical polymerization low-density polyethylene IIb! is usually in therange of 99:1 to 60:40, preferably 98:2 to 70:30, more preferably 98:2to 80:20.

When the amount of the high-pressure radical polymerization low-densitypolyethylene is less than the lower limit of the above range, theresulting composition may be improved insufficiently in the transparencyand the melt tension. On the other hand, when the amount thereof islarger than the upper limit of the above range, the resultingcomposition may considerably be deteriorated in the tensile strength andthe stress crack resistance.

The eighth ethylene copolymer composition according to the invention maycontain various additives if desired, for example, weatheringstabilizer, heat stabilizer, antistatic agent, anti-slip agent,anti-blocking agent, anti-fogging agent, lubricant, pigment, dye,nucleating agent, plasticizer, anti-aging agent, hydrochloric acidabsorbent and antioxidant, provided that the object of the invention isnot marred.

The eighth ethylene copolymer composition according to the invention canbe prepared by known processes, for example, processes described below.

(1) A process of mechanically blending the ethylene/α-olefin copolymercomposition Ib!, the high-pressure radical polymerization low-densitypolyethylene IIb!, and if necessary, other optional components by theuse of an extruder, a kneader or the like.

(2) A process comprising dissolving the ethylene/α-olefin copolymercomposition Ib!, the high-pressure radical polymerization low-densitypolyethylene IIb!, and if necessary, other optional components in anappropriate good solvent (e.g., hydrocarbon solvent such as hexane,heptane, decane, cyclohexane, benzene, toluene and xylene), and thenremoving the solvent from the resulting solution.

(3) A process comprising independently dissolving the ethylene/α-olefincopolymer composition Ib!, the high-pressure radical polymerizationlow-density polyethylene IIb!, and if necessary, other optionalcomponents in an appropriate good solvent to prepare solutions, thenmixing the solutions, and removing the solvent from the resultingmixture.

(4) A process in any combination of the above processes (1) to (3).

The eighth ethylene copolymer composition according to the presentinvention may be processed by conventional molding method, for example,air-cooling inflation molding, two-stage air-cooling inflation molding,high-speed inflation molding, T-die film molding, water-coolinginflation molding or the like, to obtain a film. The film thus obtainedhas excellent mechanical strength, and retains properties inherent ingeneral LLDPE, such as heat-sealing properties, hot-tack properties,heat resistance and blocking resistance. Further, the film is free fromsurface stickiness because each of the ethylene/α-olefin copolymer A-5!and the ethylene/α-olefin copolymer A-6! has a prominently narrowcomposition distribution. Moreover, because of low stress within thehigh-shear region, the ethylene copolymer composition can be extruded ata high speed, and thus consumption of electric power is small, resultingin economical advantage.

Films obtained from the eighth ethylene copolymer composition of theinvention are suitable for, for example, standard bags, heavy duty bags,wrapping films, materials for laminates, sugar bags, packaging bags foroily goods, packaging bags for moist goods, various packaging films suchas those for foods, bags for liquid transportation and agriculturalmaterials. The films may also be used as multi-layer films by laminatingthe films on various substrates such as a nylon substrate and apolyester substrate. Further, the films may be used for liquidtransportation bags obtained by blow molding, bottles obtained by blowmolding, tubes and pipes obtained by extrusion molding, pull-off caps,injection molded products such as daily use miscellaneous goods, fibersand large-sized molded articles obtained by rotational molding.

EFFECT OF THE INVENTION

The ethylene copolymer composition of the present invention is excellentin heat stability and melt tension, and from this ethylene copolymercomposition, a film showing high transparency, high mechanical strengthand high blocking resistance can be obtained.

EXAMPLE

The present invention is further described below with reference toexamples, but it should be construed that the present invention is in noway limited to those examples.

In this specification, physical properties of films were evaluated inthe following manner.

Haze

The haze was measured in accordance with ASTM-D-1003-61.

Gloss

The gloss was measured in accordance with JIS Z8741.

Film impact

The film impact was measured by a pendulum type film impact testerproduced by Toyo Seiki Seisakusho K.K.

Blocking force

Inflation films each having a size of 10 cm (width)×20 cm weresandwiched between two sheets of typing paper, then further sandwichedbetween glass plates, and a load of 10 kg was applied to them in an airbath of 50° C. for 24 hours. Then, the films were fitted to an open toolto separate the films at a rate of 200 mm/min. A load at the time whenthe films are separated is A (g), the blocking force F (g/cm) isdetermined by the following formula.

    F=A/width of sample

As the F value becomes smaller, blocking of the films come to hardlytake place, that is, the film has a higher blocking resistance.

Tensile test

A specimen was punched using a dumbbell (JIS No. 1) from the film in themachine direction (MD) or the transverse direction (TD) of the filmmolding direction, and a modulus in tension (YM) and an elongation atbreak (EL) of the specimen were measured under the conditions of adistance between chucks of 86 mm and a crosshead speed of 200 mm/min.

Preparation Example 1 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

7.9 kg of silica having been dried at 250° C. for 10 hours was suspendedin 121 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=1.47 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 30 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 20 liters of a toluene solution ofbis(1,3-dimethylcyclopentadienyl)zirconium dichloride (Zr=28.4 mmol/l)at 30° C. over 30 minutes, and the reaction was further carried out at30° C. for 2 hours. Then, the supernatant liquid was removed, and theresidue was washed twice with hexane to obtain a solid catalystcontaining 4.6 mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 160 liters of hexane containing 16 mol of triisobutylaluminum wasadded 4.3 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 3.5 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 3 g based on 1 g of the solidcatalyst. This ethylene polymer had an intrinsic viscosity η! of 1.27dl/g.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 20 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.048 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thereactor (gas composition: 1-hexene/ethylene=0.030,hydrogen/ethylene=0.0013, ethylene concentration=25%).

Thus, an ethylene/α-olefin copolymer (A-1-1) was obtained in an amountof 5.3 kg/hour. The copolymer had a density of 0.920 g/cm³ and a meltflow rate (MFR) of 2.0 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 112.2° C. Further,the copolymer had a melt tension (MT) of 1.8 g at 190° C. and a flowindex (FI) of 290 (l/sec). The amount of the decane-soluble portion inthe copolymer was 0.47% by weight at 23° C. The number of unsaturatedbond in the copolymer was 0.091 per 1,000 carbon atoms, and was 0.08 perone molecule of the polymer.

Physical properties of the ethylene/α-olefin copolymer (A-1-1) are setforth in Table 1.

Example 1

Preparation of a composition!

The ethylene/α-olefin copolymer (A-1-1) obtained in Preparation Example1 and a high-pressure radical polymerization low-density polyethylene(B-1-1) shown in Table 2 were dry blended in a mixing ratio of 90/10(A-1-1)/(B-1-1)!. To the resultant blend were added 0.05 part by weightof tri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1part by weight ofn-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate as aheat-resistant stabilizer and 0.05 part by weight of calcium stearate asa hydrochloric acid absorbent, each based on 100 parts by weight of theresin. Then, the resultant mixture was kneaded by a conical-taperedtwin-screw extruder (produced by Haake Buchler Instrument Inc.) at apreset temperature of 180° C., to obtain an ethylene copolymercomposition.

Film formation!

The ethylene copolymer composition obtained as above was subjected toinflation by the use of a single-screw extruder (20 mmφ·L/D=26) equippedwith a die of 25 mmφ (lip width: 0.7 mm) and a single-slit air ringunder the conditions of an air flow rate of 90 l/min, an extrusion rateof 9 g/min, a blow ratio of 1.8, a take-up rate of 2.4 m/min and aprocessing temperature of 200° C., to form a film having a thickness of30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 3.

As is evident from Table 3, the film obtained from the composition wasexcellent in optical characteristics, moldability, blocking resistanceand strength.

Reference Example 1

The procedure of film formation in Example 1 was repeated except forusing the ethylene/α-olefin copolymer (A-1-1) obtained in PreparationExample 1, to form a film having a thickness of 30 μm. Melt propertiesof the ethylene/α-olefin copolymer and physical properties of the filmformed from the copolymer are set forth in Table 3.

As is evident from Example 1 and Reference Example 1, theethylene/α-olefin copolymer was improved in moldability and opticalcharacteristics by blending it with a high-pressure radicalpolymerization low-density polyethylene. Further, the ethylene copolymercomposition was hardly reduced in the film impact as compared with theethylene/α-olefin copolymer (A-1-1), in spite that the compositioncontained a high-pressure radical polymerization low-densitypolyethylene having a low film impact.

Comparative Example 1

Preparation of an ethylene/α-olefin copolymer (C-1)!

The procedure of copolymerization of ethylene with 1-hexene inPreparation Example 1 was repeated except for replacing the zirconiumcatalyst system with a titanium type catalyst system described inJapanese Patent Publication No. 63(1988)-54289, to obtain anethylene/α-olefin copolymer (C-1). Physical properties of theethylene/α-olefin copolymer (C-1) are set forth in Table 1.

Preparation of an ethylene copolymer composition!

The ethylene/α-olefin copolymer (C-1) obtained in the above and ahigh-pressure radical polymerization low-density polyethylene (B-1-1)shown in Table 2 were used to prepare an ethylene copolymer compositionin a manner similar to that of Example 1.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 1. Melt properties of the ethylene copolymer composition andphysical properties of the film formed from the composition are setforth in Table 3.

The film obtained above had a wide composition distribution and a largeamount of sticky component, and hence the film was particularly low inthe blocking resistance. Further, as is clear from Comparative Example 1and Example 1 wherein an ethylene/α-olefin copolymer containing the samecomonomers as those of the copolymer in Comparative Example 1 and havingMT and density almost equal to those of the copolymer in ComparativeExample 1 was used, the film of Example 1 was very low in reduction ofthe film impact.

Comparative Example 2

From the ethylene/α-olefin copolymer (C-1) obtained in ComparativeExample 1, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 1.

Melt properties of the ethylene/α-olefin copolymer (C-1) and physicalproperties of the film formed from the copolymer are set forth in Table3.

Preparation Examples 2-4

The procedure of Preparation Example 1 was repeated except for varyingthe kinds of the comonomers and the amounts thereof to those set forthin Table 1, to obtain ethylene/α-olefin copolymers (A-1-2), (A-1-3) and(A-1-4).

Physical properties of the ethylene/α-olefin copolymers (A-1-2), (A-1-3)and (A-1-4) are set forth in Table 1.

Examples 2-4

The procedure for preparing the ethylene copolymer composition inExample 1 was repeated except for varying the ethylene/α-olefincopolymer to those set forth in Table 3, to prepare ethylene copolymercompositions. From the ethylene copolymer compositions thus prepared,films each having a thickness of 30 μm were formed in a manner similarto that of Example 1.

Melt properties of the ethylene copolymer compositions and physicalproperties of the films formed from the compositions are set forth inTable 3.

Reference Examples 2-4

From the ethylene/α-olefin copolymers (A-1-2), (A-1-3) and (A-1-4)obtained in Preparation Examples 2 to 4, films each having a thicknessof 30 μm were formed in a manner similar to that of Example 1.

Melt properties of the ethylene/α-olefin copolymers (A-1-2), (A-1-3) and(A-1-4) and physical properties of the films formed from the copolymersare set forth in Table 3.

Preparation Example 5

The procedure of copolymerization of ethylene with 1-hexene inPreparation Example 1 was repeated except for replacingbis(1,3-dimethylcyclopentadienyl)zirconium dichloride withethylenebis(indenyl)zirconium dichloride and varying the comonomeramount to that set forth in Table 1, to prepare an ethylene/α-olefincopolymer (A-1-5).

Physical properties of the ethylene/α-olefin copolymer (A-1-5) are setforth in Table 1.

Example 5

The ethylene/α-olefin copolymer (A-1-5) obtained in Preparation Example5 and a high-pressure radical polymerization low-density polyethylene(B-1-2) shown in Table 2 were used to prepare an ethylene copolymercomposition in a manner similar to that of Example 1. From the ethylenecopolymer composition thus prepared, a film having a thickness of 30 μmwas formed in a manner similar to that of Example 1.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 3.

Reference Example 5

The procedure of film formation in Example 1 was repeated except forusing the ethylene/α-olefin copolymer (A-1-5) obtained in PreparationExample 5, to form a film having a thickness of 30 μm.

Melt properties of the ethylene/α-olefin copolymer (A-1-5) and physicalproperties of the film formed from the copolymer are set forth in Table3.

Example 6

The ethylene/α-olefin copolymer (A-1-1) obtained in Preparation Example1 and a high-pressure radical polymerization low-density polyethylene(B-1-3) shown in Table 2 were used to prepare an ethylene copolymercomposition in a manner similar to that of Example 1. From the ethylenecopolymer composition thus prepared, a film having a thickness of 30 μmwas formed in a manner similar to that of Example 1.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 3.

Comparative Example 3

The ethylene/α-olefin copolymer (A-1-1) obtained in Preparation Example1 and a high-pressure radical polymerization low-density polyethylene(D-1) shown in Table 2 were used to prepare an ethylene copolymercomposition in a manner similar to that of Example 1. From the ethylenecopolymer composition thus prepared, a film having a thickness of 30 μmwas formed in a manner similar to that of Example 1.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 3.

As is evident from Comparative Example 3 and Reference Example 1, evenby blending the ethylene/α-olefin copolymer with such a high-pressureradical polymerization low-density polyethylene as used in ComparativeExample 3, the resulting composition was not increased in the melttension.

It has been confirmed from the examples, the comparative examples andthe reference examples described above that when the ethylene/α-olefincopolymer is blended with a specific high-pressure radicalpolymerization low-density polyethylene, the resulting composition isimproved in the moldability, and the film formed from the composition isimproved in the optical characteristics. Further, the ethylene copolymercomposition is hardly reduced in the film impact, as compared with theethylene/α-olefin copolymer only, in spite that the composition containsa high-pressure radical polymerization low-density polyethylene having alow film impact. Moreover, it has been also confirmed that a filmshowing high blocking resistance can be obtained from the ethylenecopolymer composition of the invention.

                  TABLE 1                                                         ______________________________________                                        Ethylene/α-olefin copolymer                                             ______________________________________                                                          Amount of                                                                     co-            MFR                                          Code              monomer  Density                                                                             g/10 Tm   Formula                            No.  Comonomer    mol %    g/cm.sup.3                                                                          min  °C.                                                                         (1)                                ______________________________________                                        A-1-1                                                                              1-hexene     3.0      0.920 2.0  112.2                                                                              118.0                              A-1-2                                                                              1-pentene    2.6      0.920 2.1  111.9                                                                              118.0                              A-1-3                                                                              4-methyl-1-pentene                                                                         2.3      0.921 2.0  112.0                                                                              118.4                              A-1-4                                                                              1-butene     2.5      0.926 2.0  111.5                                                                              120.4                              A-1-5                                                                              1-hexene     2.8      0.922 1.6  112.1                                                                              118.8                              C-1  1-hexene     3.6      0.922 1.0  123.2                                                                              118.8                              ______________________________________                                                                      Decane-soluble Unsatu-                          Code MT     mula   FI   Formula                                                                             portion weight                                                                         Formula                                                                             rated                            No.  g      (2)    s.sup.-1                                                                           (3)   %        (4)   bond *1                          ______________________________________                                        A-1-1                                                                              1.8    1.2    290  150   0.47     1.57  0.091                            A-1-2                                                                              1.7    1.2    270  158   0.08     1.57  0.093                            A-1-3                                                                              1.9    1.2    280  150   0.25     1.43  0.022                            A-1-4                                                                              1.9    1.2    270  150   0.57     0.90  0.091                            A-1-5                                                                              6.6    1.5    220  120   0.53     1.30  0.088                            C-1  1.8    2.2    190   75   7.9      1.30  0.250                            ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d250 wherein Tm means a melting point at th     maximum peak of the DSC endothermic curve, and d means a density.             Formula (2): MT > 2.2 × MFR.sup.-0.84 wherein MT means a melt           tension at 190° C., and MFR means a melt flow rate.                    Formula (3): FI > 75 × MFR wherein FI means a flow index, and MFR       means a melt flow rate.                                                       Formula (4): W < 80 × exp (-100(d0.88)) + 0.1  under the condition      of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (4): W < 80 × (MFR9).sup.-0.26 × exp (-100(d0.88)) +      0.1  under the condition of MFR ≦ 10 g/10 min!, wherein W means a      weight of a decanesoluble portion at 23° C.                            *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A1-1˜A1-5: Zr type catalyst, gas phase polymerization                   C1: Ti type catalyst, gas phase polymerization                           

                  TABLE 2                                                         ______________________________________                                        High-pressure radical plumerization low-density polyethylene                  MFR                      Physical property of film                            Code (g/                   Density                                                                             Haze Gloss                                                                              Film impact                        No.  10 min.) Mw/Mn   *1   (g/cm.sup.3)                                                                        %    %    kg · cm/cm                ______________________________________                                        B-1-1                                                                              5.2      9.4     4.2  0.919 15.0 14   1,050                              B-1-2                                                                              0.50     4.4     <0   0.924 7.4  51   1,750                              B-1-3                                                                              0.32     10.6    <0   0.922 --   --   --                                 D-1  66       8.9     12.4 0.915 --   --   --                                 ______________________________________                                         Remark: *1: value obtained by the formula 7.5 × log (MFR) - 1.2    

                  TABLE 3                                                         ______________________________________                                                              Mixing  Melt property of                                Compon-      Compon-  ratio   ethylene copolymer                              ent          ent      A/B     composition                                             A        B        weight                                                                              MFR    MT   FI                                        Code No. Code No. ratio g/10 min.                                                                            g    s.sup.-1                          ______________________________________                                        Ex. 1   A-1-1    B-1-1    90/10 2.1    3.1  350                               Ref. Ex. 1                                                                            A-1-1             100/0 2.0    1.8  290                               Comp. Ex. 1                                                                           C-1      B-1-1    90/10 1.0    4.0  245                               Comp. Ex. 2                                                                           C-1               100/0 1.0    1.8  190                               Ex. 2   A-1-2    B-1-1    90/10 2.1    2.9  330                               Ref. Ex. 2                                                                            A-1-2             100/0 2.1    1.7  270                               Ex. 3   A-1-3    B-1-1    90/10 2.0    3.0  340                               Ref. Ex. 3                                                                            A-1-3             100/0 2.0    1.9  280                               Ex. 4   A-1-4    B-1-1    90/10 2.0    2.9  330                               Ref. Ex. 4                                                                            A-1-4             100/0 2.0    1.9  270                               Ex. 5   A-1-5    B-1-2    90/10 1.7    8.8  220                               Ref. Ex. 5                                                                            A-1-5             100/0 1.6    6.9  220                               Ex. 6   A-1-1    B-1-3    90/10 1.8    3.7  290                               Ref. Ex. 1                                                                            A-1-1             100/0 2.0    1.8  290                               Comp. Ex. 3                                                                           A-1-1    D-1      90/10 2.2    1.8  390                               Ref. Ex. 1                                                                            A-1-1             100/0 2.0    1.8  290                               ______________________________________                                        Physical property of film                                                                                  Impact        Mold-                                     Haze   Gloss  Film impact                                                                           retention                                                                            Blocking                                                                             ability                                   %      %      kg · cm/cm                                                                   rate *1                                                                              force g/cm                                                                           *2                                 ______________________________________                                        Ex. 1  8.6    54     3,380   95     0.43   AA                                 Ref. Ex. 1                                                                           9.5    49     3,540   100    0.21   CC                                 Comp.  6.2    95     2,760   81     4.7    AA                                 Ex. 1                                                                         Comp.  11.5   44     3,400   100    4.0    CC                                 Ex. 2                                                                         Ex. 2  6.2    90     2,620   96     0.44   BB                                 Ref. Ex. 2                                                                           7.4    68     2,730   100    0.27   CC                                 Ex. 3  6.4    88     2,920   95     0.15   AA                                 Ref. Ex. 3                                                                           7.9    62     3,070   100    0.13   CC                                 Ex. 4  6.0    91     1,770   99     1.16   BB                                 Ref. Ex. 4                                                                           6.8    68     1,790   100    0.78   CC                                 Ex. 5  10.1   43     2,900   96     0.08   AA                                 Ref. Ex. 5                                                                           12.0   36     3,010   100    0.06   Ah                                 Ex. 6  12.4   28     3,490   99     0.20   AA                                 Ref. Ex. 1                                                                           9.5    49     3,540   100    0.21   CC                                 Comp.  9.4    52     3,210   91     0.29   CC                                 Ex. 3                                                                         Ref. Ex. 1                                                                           9.5    49     3,540   100    0.21   CC                                 ______________________________________                                         Remark:                                                                       Impact retention rate *1: film impact of a film formed from the ethylene      copolymer composition based on the film impact of a film formed from the      ethylene/olefin copolymer only being 100. As this value is larger, the        impact retention becomes higher.                                              Moldability *2: AA: MT ≧ 3, BB: 3 > MT ≧ 2, CC: 2 > MT     

Preparation Example 6

Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

7.9 kg of silica having been dried at 250° C. for 10 hours was suspendedin 121 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=1.47 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 30 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 20 liters of a toluene solution ofbis(1,3-dimethylcyclopentadienyl)zirconium dichloride (Zr=28.4 mmol/l)at 30° C. over 30 minutes, and the reaction was further carried out at30° C. for 2 hours. Then, the supernatant liquid was removed, and theresidue was washed twice with hexane to obtain a solid catalystcontaining 4.6 mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 160 liters of hexane containing 16 mol of triisobutylaluminum wasadded 4.3 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 3.5 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 3 g based on 1 g of the solidcatalyst. This ethylene polymer had an intrinsic viscosity η! of 1.27dl/g.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 20 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.048 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thereactor (gas composition: 1-hexene/ethylene=0.083,hydrogen/ethylene=0.0012, ethylene concentration=23%).

Thus, an ethylene/α-olefin copolymer (A-1-6) was obtained in an amountof 5.3 kg/hour. The copolymer had a density of 0.927 g/cm³ and a meltflow rate (MFR) of 1.0 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 117.8° C. Further,the copolymer had a melt tension (MT) of 3.2 g at 190° C. and a flowindex (FI) of 180 (l/sec). The amount of the decane-soluble portion inthe copolymer was 0.22% by weight at 23° C. The number of unsaturatedbond in the copolymer was 0.062 per 1,000 carbon atoms, and was 0.06 perone molecule of the polymer.

Physical properties of the ethylene/α-olefin copolymer (A-1-6) are setforth in Table 4.

Reference Example 6

Film formation!

The ethylene/α-olefin copolymer (A-1-6) obtained in Preparation Example6 was subjected to inflation by the use of a single-screw extruder (20mmφ·L/D=26) equipped with a die of 25 mmφ (lip width: 0.7 mm) and asingle-slit air ring under the conditions of an air flow rate of 90l/min, an extrusion rate of 9 g/min, a blow ratio of 1.8, a take-up rateof 2.4 m/min and a processing temperature of 200° C., to form a filmhaving a thickness of 30 μm.

Melt properties of the ethylene/α-olefin copolymer (A-1-6) and physicalproperties of the film formed from the copolymer are set forth in Table6.

Example 7

Preparation of a composition!

The ethylene/α-olefin copolymer (A-1-6) obtained in Preparation Example6 and a crystalline polyolefin (B-2-1) shown in Table 5 were dry blendedin a weight ratio of 90/10 (A-1-6)/(B-2-1)!. To the resultant blend wereadded 0.05 part by weight of tri(2,4-di-t-butylphenyl)phosphate as asecondary antioxidant, 0.1 part by weight ofn-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate as aheat-resistant stabilizer and 0.05 part by weight of calcium stearate asa hydrochloric acid absorbent, each based on 100 parts by weight of theresin. Then, the resultant mixture was kneaded by a conical-taperedtwin-screw extruder (produced by Haake Buchler Instrument Inc.) at apreset temperature of 180° C., to obtain an ethylene copolymercomposition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation in a manner similar to that of Reference Example 6, toprepare a film having a thickness of 30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 6.

As compared with Reference Example 6, the ethylene copolymer compositionobtained above was not lowered in the melt tension and the flow index(FI) within the high-shear region, and the film formed from thecomposition was improved in the rigidity.

Example 8

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 7 was repeated except for using the ethylene/α-olefin copolymer(A-1-6) obtained in Preparation Example 6 and a crystalline polyolefin(B-2-2) shown in Table 5 in a weight ratio of 90/10 (A-1-6)/(B-2-2)!, toprepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 6.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 6.

As compared with Reference Example 6, the ethylene copolymer compositionobtained above was not lowered in the melt tension and the flow index(FI) within the high-shear region, and the film formed from thecomposition was improved in the rigidity.

Example 9

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 7 was repeated except for using the ethylene/α-olefin copolymer(A-1-6) obtained in Preparation Example 6 and a crystalline polyolefin(B-2-3) shown in Table 5 in a weight ratio of 90/10 (A-1-6)/(B-2-3)!, toprepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 6.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 6.

As compared with Reference Example 6, the ethylene copolymer compositionobtained above was increased in the flow index (FI) within thehigh-shear region, and the film formed from the composition was enhancedin the rigidity.

Example 10

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 7 was repeated except for using the ethylene/α-olefin copolymer(A-1-6) obtained in Preparation Example 6 and a crystalline polyolefin(B-2-4) shown in Table 5 in a weight ratio of 90/10 (A-1-6)/(B-2-4)!, toprepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 6.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 6.

As compared with Reference Example 6, the ethylene copolymer compositionobtained above was increased in the flow index (FI) within thehigh-shear region, and the film formed from the composition was enhancedin the rigidity.

Example 11

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 7 was repeated except for using the ethylene/α-olefin copolymer(A-1-6) obtained in Preparation Example 6 and a crystalline polyolefin(B-2-5) shown in Table 5 in a weight ratio of 90/10 (A-1-6)/(B-2-5)!, toprepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 6.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 6.

As compared with Reference Example 6, the ethylene copolymer compositionobtained above was increased in the flow index (FI) within thehigh-shear region, and the film formed from the composition was enhancedin the rigidity.

                  TABLE 4                                                         ______________________________________                                        Ethylene/α-olefin copolymer                                             ______________________________________                                                          Amount of                                                                     co-            MFR                                          Code              monomer  Density                                                                             g/10 Tm   Formula                            No.  Comonomer    mol %    g/cm.sup.3                                                                          min  °C.                                                                         (1)                                ______________________________________                                        A-1-6                                                                              1-hexene     1.9      0.927 1.0  117.8                                                                              120.8                              ______________________________________                                                    For-              Decane-soluble Unsatu-                          Code MT     mula   FI   Formula                                                                             portion weight                                                                         Formula                                                                             rated                            No.  g      (2)    s.sup.-1                                                                           (3)   %        (4)   bond *1                          ______________________________________                                        A-1-6                                                                              3.2    2.2    180  75    0.22     0.83  0.062                            ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d250 wherein Tm means the maximum peak          temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT > 2.2 × MFR.sup.-0.84 wherein MT means a melt           tension at 190° C., and MFR means a melt flow rate.                    Formula (3): FI > 75 × MFR wherein FI means a flow index, and MFR       means a melt flow rate.                                                       Formula (4): W < 80 × exp (-100(d0.88)) + 0.1  under the condition      of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (4): W < 80 × (MFR9).sup.-0.26 × exp (-100(d0.88)) +      0.1  under the condition of MFR > 10 g/10 min!, wherein W means a weight      of a decanesoluble portion at 23° C.                                   *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A1-6: Zr type catalyst, gas phase polymerization                         

                  TABLE 5                                                         ______________________________________                                        Code  Composition (mol %) MFR       Density                                   No.   Ethylene  Propylene                                                                              Butene (g/10 min)                                                                            (g/cm.sup.3)                          ______________________________________                                        B-2-1 100       --       --     5.0     0.968                                 B-2-2 99.8      --       0.2    0.65    0.963                                 B-2-3 3.4       95.0     1.6    6.8     0.910                                 B-2-4 --        100      --     6.5     0.910                                 B-2-5 --        --       100    2.0     0.908                                 ______________________________________                                         Remark:                                                                       MFR measuring temperature                                                     B2-1, B2-2: 190° C.                                                    B2-3˜B2-5: 230° C.                                          

                  TABLE 6                                                         ______________________________________                                        Compon-     Compon-  Mixing                                                   ent         ent      ratio A/B                                                                              Melt property                                          A        B        weight MFR    MT   FI                                       Code No. Code No. ratio  g/10 min                                                                             g    s.sup.-1                          ______________________________________                                        Ref. Ex. 6                                                                           A-1-6    --       100/0  1.0    3.2  180                               Ex. 7  A-1-6    B-2-1    90/10  1.2    3.1  210                               Ex. 8  A-1-6    B-2-2    90/10  1.0    3.4  220                               Ex. 9  A-1-6    B-2-3    90/10  1.1    3.2  370                               Ex. 10 A-1-6    B-2-4    90/10  1.1    3.2  240                               Ex. 11 A-1-6    B-2-5    90/10  1.1    3.2  310                               ______________________________________                                        Physical property of film                                                     Haze       Tensile test (MD)                                                                            Tensile test (TD)                                          %       YM kg/cm.sup.2                                                                           EL %  YM kg/cm.sup.2                                                                         EL %                                 ______________________________________                                        Ref. Ex. 6                                                                           10.0    4,100      570   4,400    620                                  Ex. 7  10.0    4,800      600   5,900    650                                  Ex. 8  12.7    4,600      600   5,600    700                                  Ex. 9  9.9     5,300      610   5,600    650                                  Ex. 10 10.3    5,900      600   6,300    650                                  Ex. 11 13.6    4,200      560   4,900    630                                  ______________________________________                                    

Preparation Example 7 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

7.9 kg of silica having been dried at 250° C. for 10 hours was suspendedin 121 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=1.47 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 30 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 20 liters of a toluene solution ofbis(1,3-dimethylcyclopentadienyl)zirconium dichloride (Zr=28.4 mmol/l)at 30° C. over 30 minutes, and the reaction was further carried out at30° C. for 2 hours. Then, the supernatant liquid was removed, and theresidue was washed twice with hexane to obtain a solid catalystcontaining 4.6 mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 160 liters of hexane containing 16 mol of triisobutylaluminum wasadded 4.3 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 3.5 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 3 g based on 1 g of the solidcatalyst. The ethylene polymer had an intrinsic viscosity η! of 1.27dl/g.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 20 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.048 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thepolymerizer (gas composition: 1-hexene/ethylene=0.083,hydrogen/ethylene=0.0012, ethylene concentration=23%).

Thus, an ethylene/α-olefin copolymer (A-1-7) was obtained in an amountof 5.3 kg/hour. The copolymer had a density of 0.927 g/cm³ and a meltflow rate (MFR) of 1.0 g/10 min. The number of unsaturated bond in thecopolymer was 0.062 per 1,000 carbon atoms, and was 0.06 per onemolecule of the polymer. The temperature at the maximum peak of the DSCendothermic curve (Tm) of the copolymer was 117.8° C. The amount of thedecane-soluble portion in the copolymer was 0.22% by weight at 23° C.

Physical properties of the ethylene/α-olefin copolymer (A-1-7) are setforth in Table 7.

Reference Example 7

Film formation!

The ethylene/α-olefin copolymer (A-1-7) obtained in Preparation Example7 was subjected to inflation by the use of a single-screw extruder (20mmφ·L/D=26) equipped with a die of 25 mmφ (lip width: 0.7 mm) and asingle-slit air ring under the conditions of an air flow rate of 90l/min, an extrusion rate of 9 g/min, a blow ratio of 1.8, a take-up rateof 2.4 m/min and a processing temperature of 200° C., to form a filmhaving a thickness of 30 μm.

Melt properties of the ethylene/α-olefin copolymer (A-1-7) and physicalproperties of the film formed from the copolymer are set forth in Table9.

Example 12

Preparation of a composition!

The ethylene/α-olefin copolymer (A-1-7) obtained in Preparation Example7 and an olefin type elastomer (B-3-1) (density: 0.88 g/cm³) shown inTable 8 were dry blended in a weight ratio of 90/10 (A-1-7)/(B-3-1)!. Tothe resultant blend were added 0.05% by weight oftri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1% byweight of n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate asa heat-resistant stabilizer and 0.05% by weight of calcium stearate as ahydrochloric acid absorbent, each based on 100 parts by weight of theresin. Then, the resultant mixture was kneaded by a conical-taperedtwin-screw extruder (produced by Haake Buchler Instrument Inc.) at apreset temperature of 180° C., to obtain an ethylene copolymercomposition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation in a manner similar to that of Reference Example 7, toprepare a film having a thickness of 30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 9.

As compared with Reference Example 7, the inflation film obtained abovewas improved in the film impact without deterioration of thetransparency and the moldability (MT, FI).

Example 13

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 12 was repeated except for using the ethylene/α-olefin copolymer(A-1-7) obtained in Preparation Example 7 and an olefin type elastomer(B-3-2) (density: 0.87 g/cm³) shown in Table 8 in a weight ratio of90/10 (A-1-7)/(B-3-2)!, to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition prepared in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 7.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 9.

As compared with Reference Example 7, the inflation film obtained abovewas improved in the film impact without deterioration of thetransparency and the moldability (MT, FI).

Example 14

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 12 was repeated except for using the ethylene/α-olefin copolymer(A-1-7) obtained in Preparation Example 7 and an olefin type elastomer(B-3-3) (density: 0.87 g/cm³) shown in Table 8 in a weight ratio of90/10 (A-1-7)/(B-3-3)!, to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 7.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 9.

As compared with Reference Example 7, the inflation film obtained abovewas improved in the film impact without deterioration of thetransparency and the moldability (MT, FI).

                  TABLE 7                                                         ______________________________________                                        Ethylene/α-olefin copolymer                                             ______________________________________                                                          Amount of                                                                     co-            MFR                                          Code              monomer  Density                                                                             g/10 Tm   Formula                            No.  Comonomer    mol %    g/cm.sup.3                                                                          min  °C.                                                                         (1)                                ______________________________________                                        A-1-7                                                                              1-hexene     1.9      0.927 1.0  117.8                                                                              120.8                              ______________________________________                                                                      Decane-soluble Unsatu-                          Code MT     mula   FI   Formula                                                                             portion weight                                                                         Formula                                                                             rated                            No.  g      (2)    s.sup.-1                                                                           (3)   %        (4)   bond *1                          ______________________________________                                        A-1-7                                                                              3.2    2.2    180  75    0.22     0.83  0.062                            ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d250 wherein Tm means the maximum peak          temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT > 2.2 × MFR.sup.-0.84 wherein MT means a melt           tension at 190° C., and MFR means a melt flow rate.                    Formula (3): FI > 75 × MFR wherein FI means a flow index, and MFR       means a melt flow rate.                                                       Formula (4): W < 80 × exp (-100(d0.88)) + 0.1  under the condition      of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (4): W < 80 × (MFR9).sup.-0.26 × exp (-100(d0.88)) +      0.1  under the condition of MFR ≦ 10 g/10 min!, wherein W means a      weight of a decanesoluble portion at 23° C.                            *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A1-7: Zr type catalyst, gas phase polymerization                         

                  TABLE 8                                                         ______________________________________                                        Code  Composition (mol %)   MFR      Density                                  No.   Ethylene Propylene                                                                              Butene                                                                              ENB   (g/10 min)                                                                           (g/cm.sup.3)                       ______________________________________                                        B-3-1 89       --       11    --    3.6    0.88                               B-3-2 80       20       --    --    1.0    0.87                               B-3-3 74       24       --    2     0.2    0.87                               ______________________________________                                         Remark:                                                                       ENB: ethylidene norbornene                                               

                                      TABLE 9                                     __________________________________________________________________________                     Mixing       Physical property                                                ratio                                                                             Melt property                                                                          of film                                         Component  Component                                                                           A/B MFR         Film                                         A          B     weight                                                                            g/10                                                                             MT FI Haze                                                                             impact                                       Code No.   Code No.                                                                            ratio                                                                             min                                                                              g  s.sup.-1                                                                         %  kg · cm/cm                          __________________________________________________________________________    Ref. Ex. 7                                                                         A-1-7 --    100/0                                                                             1.0                                                                              3.2                                                                              180                                                                              10.0                                                                             2,210                                        Ex. 12                                                                             A-1-7 B-3-1 90/10                                                                             1.2                                                                              3.3                                                                              210                                                                              9.5                                                                              2,620                                        Ex. 13                                                                             A-1-7 B-3-2 90/10                                                                             1.0                                                                              3.6                                                                              180                                                                              9.0                                                                              2,910                                        Ex. 14                                                                             A-1-7 B-3-3 90/10                                                                             0.8                                                                              4.3                                                                              150                                                                              9.9                                                                              2,910                                        __________________________________________________________________________

Preparation Example 8 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

7.9 kg of silica having been dried at 250° C. for 10 hours was suspendedin 121 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=1.47 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 30 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation. The solidcomponent obtained above was washed twice with toluene, and then againsuspended in 125 liters of toluene. To the reaction system was dropwiseadded 20 liters of a toluene solution ofbis(1,3-dimethylcyclopentadienyl)zirconium dichloride (Zr=28.4 mmol/l)at 30° C. over 30 minutes, and the reaction was further carried out at30° C. for 2 hours. Then, the supernatant liquid was removed, and theresidue was washed twice with hexane to obtain a solid catalystcontaining 4.6 mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 160 liters of hexane containing 16 mol of triisobutylaluminum wasadded 4.3 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 3.5 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 3 g based on 1 g of the solidcatalyst. The ethylene polymer had an intrinsic viscosity η! of 1.27dl/g.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 18 kg/cm² -G and apolymerization temperature of 75° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.05 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thereactor (gas composition: 1-hexene/ethylene=0.041,hydrogen/ethylene=0.0011, ethylene concentration=10%).

Thus, an ethylene/α-olefin copolymer (A-2-1) was obtained in an amountof 6.0 kg/hour. The copolymer had a density of 0.906 g/cm³ and a meltflow rate (MFR) of 0.32 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 92.5° C. Further,the copolymer had a melt tension (MT) of 6.2 g at 190° C. and a flowindex (FI) of 89 (l/sec). The amount of the decane-soluble portion inthe copolymer was 0.52% by weight at room temperature. The number ofunsaturated bond in the copolymer was 0.090 per 1,000 carbon atoms, andwas 0.90 per one molecule of the polymer.

Physical properties of the ethylene/α-olefin copolymer (A-2-1) are setforth in Table 10.

Example 15

Preparation of an ethylene/α-olefin copolymer composition!

The ethylene/α-olefin copolymer (A-2-1) (density: 0.906 g/cm³) obtainedin Preparation Example 8 and an ethylene/α-olefin copolymer (A-3-1)(density: 0.949 g/cm³) prepared in the same manner as described inPreparation Example 8 except for adjusting the comonomer amount to thatset forth in Table 10 were melt kneaded in a weight ratio of 57/43(A-2-1)/(A-3-1)!, to prepare an ethylene/α-olefin copolymer composition(L-1-1).

Physical properties of the ethylene/α-olefin copolymer (A-3-1) are setforth in Table 10, and physical properties of the ethylene/α-olefincopolymer composition (L-1-1) are set forth in Table 11.

Preparation of an ethylene copolymer composition!

The ethylene/α-olefin copolymer composition (L-1-1) and a high-pressureradical polymerization low-density polyethylene (B-1-4) shown in Table12 were dry blended in a mixing ratio of 90/10 (L-1-1)/(B-1-4)!. To theresultant blend were added 0.05 part by weight oftri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1 partby weight of n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionateas a heat-resistant stabilizer and 0.05 part by weight of calciumstearate as a hydrochloric acid absorbent, each based on 100 parts byweight of the resin. Then, the resultant mixture was kneaded by aconical-tapered twin-screw extruder (produced by Haake BuchlerInstrument Inc.) at a preset temperature of 180° C., to obtain anethylene copolymer composition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation by the use of a single-screw extruder (20 mmφ·L/D=26)equipped with a die of 25 mmφ (lip width: 0.7 mm) and a single-slit airring under the conditions of an air flow rate of 90 l/min, an extrusionrate of 9 g/min, a blow ratio of 1.8, a take-up rate of 2.4 m/min and aprocessing temperature of 200° C., to form a film having a thickness of30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

Reference Example 8

Film formation!

The procedure of film formation in Example 15 was repeated except forusing the ethylene/α-olefin copolymer composition (L-1-1) prepared inExample 15, to form a film having a thickness of 30 μm.

Melt properties of the ethylene/α-olefin copolymer composition (L-1-1)and physical properties of the film formed from the composition are setforth in Table 13.

It was confirmed from Example 15 and Reference Example 8 that theethylene/α-olefin copolymer composition was increased in the melttension by blending it with a high-pressure radical polymerizationlow-density polyethylene, and the film formed from the compositioncontaining the polyethylene was enhanced in the transparency.

Example 16

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (A-2-2) (density: 0.916 g/cm³) and anethylene/α-olefin copolymer (A-3-2) (density: 0.931 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 8 except for adjusting the comonomer amount to thatset forth in Table 10, were melt kneaded in a weight ratio of 70/30(A-2-2)/(A-3-2)!, to obtain an ethylene/α-olefin copolymer composition(L-1-2).

Physical properties of the ethylene/α-olefin copolymer (A-3-2) are setforth in Table 10, and physical properties of the ethylene/α-olefincopolymer composition (L-1-2) are set forth in Table 11.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 15 was repeated except for using the ethylene/α-olefin copolymercomposition (L-1-2), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 15.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

Reference Example 9

Film formation!

From the ethylene/α-olefin copolymer composition (L-1-2) prepared inExample 16, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 15.

Melt properties of the ethylene/α-olefin copolymer composition (L-1-2)and physical properties of the film formed from the composition are setforth in Table 13.

It was confirmed from Example 16 and Reference Example that theethylene/α-olefin copolymer composition was increased in the melttension by blending it with a high-pressure radical polymerizationlow-density polyethylene, and the film formed from the compositioncontaining the polyethylene was enhanced in the transparency.

Example 17

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (A-2-3) (density: 0.907 g/cm³) and anethylene/α-olefin copolymer (A-3-3) (density: 0.943 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 8 except for adjusting the comonomer amount to thatset forth in Table 10, were melt kneaded in a weight ratio of 60/40(A-2-3)/(A-3-3)!, to obtain an ethylene/α-olefin copolymer composition(L-1-3).

Physical properties of the ethylene/α-olefin copolymers (A-2-3) and(A-3-3) are set forth in Table 10, and physical properties of theethylene/α-olefin copolymer composition (L-1-3) are set forth in Table11.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 15 was repeated except for using the ethylene/α-olefin copolymercomposition (L-1-3), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 15.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

Reference Example 10

Film formation!

From the ethylene/α-olefin copolymer composition (L-1-3) obtained inExample 17, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 15.

Melt properties of the ethylene/α-olefin copolymer composition (L-1-3)and physical properties of the film formed from the composition are setforth in Table 13.

It was confirmed from Example 17 and Reference Example 10 that theethylene/α-olefin copolymer composition was enhanced in the transparencyand the melt tension by blending it with a high-pressure radicalpolymerization low-density polyethylene.

Comparative Example 4

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (C-2) (density: 0.915 g/cm³) and anethylene/α-olefin copolymer (C-3) (density: 0.933 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 8 except for replacing the zirconium catalyst systemwith a titanium type catalyst system described in Japanese PatentPublication No. 63(1988)-54289, and adjusting the comonomer amount tothat set forth in Table 10, were melt kneaded in a weight ratio of 60/40(C-2)/(C-3)!, to obtain an ethylene/α-olefin copolymer composition(L-1-5).

Physical properties of the ethylene/α-olefin copolymers (C-2) and (C-3)are set forth in Table 10, and physical properties of theethylene/α-olefin copolymer composition (L-1-5) are set forth in Table11.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 15 was repeated except for using the ethylene/α-olefin copolymercomposition (L-1-5), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 15.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

The ethylene copolymer composition obtained above was lower in the melttension than the ethylene/α-olefin copolymer composition (L-1-3) ofExample 17 having almost the same MFR and density, and the film obtainedabove was inferior to the film formed from the ethylene/α-olefincopolymer composition (L-1-3) of Example 17 in the film impact and theblocking resistance.

Comparative Example 5

Preparation of an ethylene/α-olefin copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 15 was repeated except for using an ethylene/α-olefin copolymer(C-4) prepared in the same manner as described in Preparation Example 8except for adjusting the comonomer amount to that set forth in Table 10,to prepare an ethylene copolymer composition.

Physical properties of the ethylene/α-olefin copolymer (C-4) are setforth in Table 10.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 15.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

The ethylene copolymer composition obtained above was lower in the flowindex within the high-shear region as compared with theethylene/α-olefin copolymer composition (L-1-1) of Example 15 havingalmost the same MFR and density, and the film obtained above wasinferior to the film formed from the ethylene/α-olefin copolymercomposition (L-1-1) of Example 15 in the film impact and the blockingresistance.

Example 18

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (A-2-4) (density: 0.916 g/cm³) preparedin the same manner as described in Preparation Example 8 except foradjusting the comonomer amount to that set forth in Table 10 and anethylene/α-olefin copolymer (A-3-4) (density: 0.924 g/cm³) prepared inthe same manner as described in Preparation Example 8 except forreplacing bis(1,3-dimethylcyclopentadienyl)zirconium dichloride withbis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride andadjusting the comonomer amount to that set forth in Table 10 were meltkneaded in a weight ratio of 20/80 (A-2-4)/(A-3-4)!, to obtain anethylene/α-olefin copolymer composition (L-1-4).

Physical properties of the ethylene/α-olefin copolymers (A-2-4) and(A-3-4) are set forth in Table 10, and physical properties of theethylene/α-olefin copolymer composition (L-1-4) are set forth in Table11.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 15 was repeated except for using the ethylene/α-olefin copolymercomposition (L-1-4), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 15.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 13.

Reference Example 11

Film formation!

From the ethylene/α-olefin copolymer composition (L-1-4) prepared inExample 18, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 15.

Melt properties of the ethylene/α-olefin copolymer composition (L-1-4)and physical properties of the film formed from the composition are setforth in Table 13.

It was confirmed from Example 18 and Reference Example 11 that theethylene/α-olefin copolymer composition was increased in the melttension by blending it with a high-pressure radical polymerizationlow-density polyethylene.

                                      TABLE 10                                    __________________________________________________________________________                          Density                                                 Code No.                                                                           Comonomer                                                                           Amount of comonomer                                                                      g/cm3                                                                              MFR g/10 min                                                                          η! g/dl                                __________________________________________________________________________    A-2-1                                                                              1-hexene                                                                            4.9        0.906                                                                              0.32   1.91                                        A-2-2                                                                              1-hexene                                                                            3.3        0.916                                                                              0.24   2.00                                        A-2-3                                                                              1-hexene                                                                            4.8        0.907                                                                              0.35   1.88                                        A-2-4                                                                              1-hexene                                                                            3.3        0.916                                                                              0.24   2.00                                        C-2  1-hexene                                                                            6.1        0.915                                                                              0.65   2.00                                        A-3-1                                                                              1-hexene                                                                            0.9        0.949                                                                              10.7   1.11                                        A-3-2                                                                              1-hexene                                                                            1.7        0.931                                                                              123    0.72                                        A-3-3                                                                              1-hexene                                                                            1.0        0.943                                                                              165    0.58                                        A-3-4                                                                              1-hexene                                                                            2.8        0.924                                                                              2.1    0.59                                        C-3  1-hexene                                                                            2.8        0.933                                                                              19.2   1.04                                        C-4  1-hexene                                                                            1.9        0.927                                                                              1.0    1.60                                        __________________________________________________________________________                             Decane-                                                                       soluble  Un-                                         Code                                                                             Tm Formula                                                                           MT Formula                                                                           FI  Formula                                                                           portion                                                                            Formula                                                                           saturated                                   No.                                                                              °C.                                                                       (1) g  (2) s.sup.-1                                                                          (3) weight %                                                                           (4) bond *1                                     __________________________________________________________________________    A-2-1                                                                            92.5                                                                             112.4                                                                             6.2                                                                              5.7   89                                                                              24  0.52 6.04                                                                              0.09                                        A-2-2                                                                            107.0                                                                            116.4                                                                             7.7                                                                              7.3   63                                                                              18  0.15 2.29                                                                              0.16                                        A-2-3                                                                            92.8                                                                             112.8                                                                             5.9                                                                              5.3   92                                                                              27  0.55 5.48                                                                              0.12                                        A-2-4                                                                            107.0                                                                            116.4                                                                             7.7                                                                              7.3   63                                                                              18  0.15 2.29                                                                              0.16                                        C-2                                                                              120.3                                                                            116.0                                                                             2.8                                                                              3.2  140                                                                              49  13.50                                                                              2.50                                                                              0.23                                        A-3-1                                                                            120.1                                                                            129.6                                                                             0.1>                                                                             --   1390                                                                             --  0.08 0.19                                                                              0.06                                        A-3-2                                                                            116.8                                                                            122.4                                                                             0.1>                                                                             --  11700                                                                             --  1.25 1.77                                                                              0.19                                        A-3-3                                                                            118.6                                                                            127.2                                                                             0.1>                                                                             --  12400                                                                             --  0.45 0.65                                                                              0.08                                        A-3-4                                                                            115.0                                                                            119.6                                                                             0.9                                                                              --   130                                                                              --  0.08 1.08                                                                              0.10                                        C-3                                                                              128.0                                                                            123.2                                                                             0.1>                                                                             --   1440                                                                             --  2.20 0.83                                                                              0.28                                        C-4                                                                              117.8                                                                            120.8                                                                             3.2                                                                              2.2  180                                                                              75  0.22 0.83                                                                              0.06                                        __________________________________________________________________________     Remark:                                                                       Formula (1): Tm < 400 × d250 wherein Tm means the maximum peak          temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT > 2.2 × MFR.sup.-0.84 wherein MT means a melt           tension at 190° C., and MFR means a melt flow rate.                    Formula (3): FI > 75 × MFR wherein FI means a flow index, and MFR       means a melt flow rate.                                                       Formula (4): W < 80 × exp (-100(d0.88)) + 0.1  under the condition      of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at room temperature.                                                  Formula (4): W < 80 × (MFR9).sup.-0.26 × exp (-100(d0.88)) +      0.1  under the condition of MFR > 10 g/10 min!, wherein W means a weight      of a decanesoluble portion at room temperature.                               *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A2-1˜A2-4, A3-1˜A3-4, C4: Zr type catalyst, gas phase             polymerization                                                                C2, C3: Ti type catalyst, gas phase polymerization                       

                  TABLE 11                                                        ______________________________________                                                            Mixing                                                    Compon-             ratio         Melt property                               ent A     Component A/B     Density                                                                             MFR                                         Code      B         (weight d     g/10 MT   FI                                No.       Code No.  ratio)  g/cm.sup.3                                                                          min  g    s.sup.-1                          ______________________________________                                        L-1-1                                                                              A-2-1    A-3-1     57/43 0.926 1.1  3.3  290                             L-1-2                                                                              A-2-2    A-3-2     70/30 0.922 0.9  3.9  260                             L-1-3                                                                              A-2-3    A-3-3     60/40 0.921 2.0  2.4  520                             L-1-4                                                                              A-2-4    A-3-4     20/80 0.922 1.4  2.7  120                             L-1-5                                                                              C-2      C-3       60/40 0.922 2.0  1.0  360                             ______________________________________                                    

                  TABLE 12                                                        ______________________________________                                        High-pressure radical polymerization low-density polyethylene                 MFR                      Physical property of film                            Code (g/                   Density                                                                             Haze Gloss                                                                              Film impact                        No.  10 min.) Mw/Mn   *1   (g/cm.sup.3)                                                                        %    %    kg · cm/cm                ______________________________________                                        B-1-4                                                                              0.50     4.4     <0   0.924 7.4  51   1,750                              ______________________________________                                         Remark: *1: value obtained by the formula 7.5 × log (MFR) - 1.2    

                  TABLE 13                                                        ______________________________________                                                                      Melt property of                                Compon-    Compon-  Mixing ratio                                                                            ethylene copolymer                              ent        ent      A I/B II  composition                                           A I      B II     (weight MFR    MT   FI                                      Code No. Code No. ratio)  g/10 min                                                                             g    s.sup.-1                          ______________________________________                                        Ex. 15                                                                              L-1-1    B-1-4    90/10   1.0    4.6  290                               Ref.  L-1-1    --       100/0   1.1    3.3  290                               Ex. 8                                                                         Ex. 16                                                                              L-1-2    B-1-4    90/10   0.9    5.1  300                               Ref.  L-1-2    --       100/0   0.9    3.9  300                               Ex. 9                                                                         Ex. 17                                                                              L-1-3    B-1-4    90/10   1.8    3.2  520                               Ref.  L-1-3    --       100/0   2.0    1.8  520                               Ex. 10                                                                        Ex. 18                                                                              L-1-4    B-1-4    90/10   1.3    3.5  120                               Ref.  L-1-4    --       100/0   1.4    2.7  120                               Ex. 11                                                                        Comp. L-1-5    B-1-4    90/10   1.8    2.3  370                               Ex. 4                                                                         Comp. C-4      B-1-4    90/10   0.9    4.6  190                               Ex. 5                                                                         ______________________________________                                        Physical property of film                                                             Haze    Film impact                                                                              Blocking force                                                                         Moldability                                       %       kg · cm/cm                                                                      g/cm     *                                         ______________________________________                                        Ex. 15  8.8     3,320      0        AA                                        Ref. Ex. 8                                                                            10.5    5,250      0        AA                                        Ex. 16  9.0     4,200      0        AA                                        Ref. Ex. 9                                                                            10.2    7,030      0        AA                                        Ex. 17  8.9     3,450      0        AA                                        Ref. Ex. 10                                                                           10.5    5,770      0        BB                                        Ex. 18  8.2     2,450      0.17     AA                                        Ref. Ex. 11                                                                           7.1     2,600      0.17     BB                                        Comp. Ex. 4                                                                           11.5    2,820      6.7      BB                                        Comp. Ex. 5                                                                           9.3     2,200      0.13     AA                                        ______________________________________                                         Remark:                                                                       Moldability *:                                                                AA: MT ≧ 3, BB: 2 ≦ MT < 3, CC: MT < 2                     

Preparation Example 9 Preparation of an ethylene/α-olefin copolymer

Preparation of a catalyst!

6.3 kg of silica having been dried at 250° C. for 10 hours was suspendedin 100 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=0.96 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 60 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 15 liters of a toluene solution ofbis(n-butylcyclopentadienyl)zirconium dichloride (Zr=42.7 mmol/l) at 30°C. over 30 minutes, and the reaction was further carried out at 30° C.for 2 hours. Then, the supernatant liquid was removed, and the residuewas washed twice with hexane to obtain a solid catalyst containing 6.2mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 300 liters of hexane containing 14 mol of triisobutylaluminum wasadded 8.5 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 7 hours to obtain a prepolymerized catalyst containingpolyethylene in an amount of 10 g based on 1 g of the solid catalyst.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 18 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.15 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thereactor (gas composition: 1-hexene/ethylene=0.020,hydrogen/ethylene=6.6×10⁻⁴, ethylene concentration=16%).

Thus, an ethylene/α-olefin copolymer (A-4-1) was obtained in an amountof 5.0 kg/hour. The copolymer had a density of 0.923 g/cm³ and a meltflow rate (MFR) of 1.1 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 116.8° C. Further,the copolymer had a melt tension (MT) of 1.5 g. The amount of thedecane-soluble portion in the copolymer was 0.02% by weight at 23° C.The number of unsaturated bond in the copolymer was 0.09 per 1,000carbon atoms, and was 0.16 per one molecule of the polymer. The B valueindicating the α-olefin distribution in the copolymer chain was 1.02.

Physical properties of the ethylene/α-olefin copolymer (A-4-1) are setforth in Table 14.

Example 19

Preparation of a composition!

The ethylene/α-olefin copolymer (A-4-1) obtained in Preparation Example9 and a high-pressure radical polymerization low-density polyethylene(B-4-2) shown in Table 15 were dry blended in a mixing ratio of 90/10(A-4-1)/(B-4-2)!. To the resultant blend were added 0.05 part by weightof tri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1part by weight ofn-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate as aheat-resistant stabilizer and 0.05 part by weight of calcium stearate asa hydrochloric acid absorbent, each based on 100 parts by weight of theresin. Then, the resultant mixture was kneaded by a conical-taperedtwin-screw extruder (produced by Haake Buchler Instrument Inc.) at apreset temperature of 180° C., to obtain an ethylene copolymercomposition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation by the use of a single-screw extruder (20 mmφ·L/D=26)equipped with a die of 25 mmφ (lip width: 0.7 mm) and a single-slit airring under the conditions of an air flow rate of 90 l/min, an extrusionrate of 9 g/min, a blow ratio of 1.8, a take-up rate of 2.4 m/min and aprocessing temperature of 200° C., to form a film having a thickness of30 μm. Melt properties of the ethylene copolymer composition andphysical properties of the film formed from the composition are setforth in Table 16.

Example 20

The procedure for preparing the ethylene copolymer composition inExample 19 was repeated except for varying the mixing ratio of theethylene/α-olefin copolymer (A-4-1) to the high-pressure radicalpolymerization low-density polyethylene (B-4-2) to 75/25(A-4-1)/(B-4-2)!, to prepare an ethylene copolymer composition. From theethylene copolymer composition, a film having a thickness of 30 μm wasformed in a manner similar to that of Example 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 16.

Example 21

The procedure for preparing the ethylene copolymer composition inExample 19 was repeated except for replacing the high-pressure radicalpolymerization low-density polyethylene (B-4-2) with a high-pressureradical polymerization low-density polyethylene (B-4-1) shown in Table15, to prepare an ethylene copolymer composition. From the ethylenecopolymer composition, a film having a thickness of 30 μm was formed ina manner similar to that of Example 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 16.

Reference Example 12

From the ethylene/α-olefin copolymer (A-4-1) obtained in PreparationExample 9, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 19.

Melt properties of the ethylene/α-olefin copolymer (A-4-1) and physicalproperties of the film formed from the copolymer are set forth in Table16.

Comparative Example 6

Preparation of an ethylene/α-olefin copolymer (C-5)!

The procedure of Preparation Example 9 was repeated except for replacingthe zirconium catalyst system with a titanium type catalyst systemdescribed in Japanese Patent Publication No. 63(1988)-54289, andadjusting the comonomer amount to that set forth in Table 14, to preparean ethylene/α-olefin copolymer (C-5). Physical properties of theethylene/α-olefin copolymer (C-5) thus obtained are set forth in Table14.

Preparation of a composition!

The ethylene/α-olefin copolymer (C-5) obtained in the above and ahigh-pressure radical polymerization low-density polyethylene (B-4-1)shown in Table 15 were used to prepare an ethylene copolymer compositionin a manner similar to that of Example 19.

Film formation!

From the ethylene copolymer composition prepared in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 16.

As shown in Table 16, the film obtained above was poor in the filmimpact and had a wide composition distribution and a large amount ofsticky component, so that the film was deteriorated in the blockingresistance. Further, when Comparative Example 6 was compared withExample 21 wherein an ethylene/α-olefin copolymer having the samecomonomers and almost the same MFR and density as those of theethylene/α-olefin copolymer of Comparative Example 6 was used, the filmof Example 21 was prominently improved in the haze.

Comparative Example 7

From the ethylene/α-olefin copolymer (C-5) obtained in ComparativeExample 6, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 19.

Melt properties of the ethylene/α-olefin copolymer (C-5) and physicalproperties of the film formed from the copolymer are set forth in Table16.

Preparation Example 10-12

The procedure of Preparation Example 9 was repeated except for varyingthe kinds of the comonomers and the amounts thereof to those set forthin Table 14, to prepare ethylene/α-olefin copolymers (A-4-2), (A-4-3)and (A-4-4). Physical properties of the ethylene/α-olefin copolymers(A-4-2), (A-4-3) and (A-4-4) thus obtained are set forth in Table 14.

Examples 22-24

The procedure for preparing the ethylene copolymer composition inExample 19 was repeated except for using the ethylene/α-olefincopolymers (A-4-2), (A-4-3) and (A-4-4) obtained in Preparation Examples10 to 12, respectively, and using a high-pressure radical polymerizationlow-density polyethylene (B-4-1) shown in Table 15, to prepare ethylenecopolymer compositions. From each of the ethylene copolymercompositions, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 19.

Melt properties of the ethylene copolymer compositions and physicalproperties of the films formed from the compositions are set forth inTable 16.

Reference Examples 13-15

From each of the ethylene/α-olefin copolymers (A-4-2), (A-4-3) and(A-4-4).obtained in Preparation Examples 10 to 12, a film having athickness of 30 μm was formed in a manner similar to that of Example 19.

Melt properties of the ethylene/α-olefin copolymers (A-4-2), (A-4-3) and(A-4-4) and physical properties of the films formed from the copolymersare set forth in Table 16.

Preparation Examples 13 & 14

The procedure of Preparation Example 9 was repeated except for replacingbis(n-butylcyclopentadienyl)zirconium dichloride withbis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride and varyingthe comonomer composition to that set forth in Table 14, to prepareethylene/α-olefin copolymers (A-4-5) and (A-4-6). Physical properties ofthe ethylene/α-olefin copolymers (A-4-5) and (A-4-6) thus obtained areset forth in Table 14.

Examples 25 & 26

The procedure for preparing the ethylene copolymer composition inExample 19 was repeated except for using the ethylene/α-olefincopolymers (A-4-5) and (A-4-6) obtained in Preparation Example 13 and14, respectively, and using a high-pressure radical polymerizationlow-density polyethylene (B-4-1) shown in Table 15, to prepare ethylenecopolymer compositions. From each of the ethylene copolymercompositions, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 19.

Melt properties of the ethylene copolymer compositions and physicalproperties of the films formed from the compositions are set forth inTable 16.

Reference Examples 16 & 17

From each of the ethylene/α-olefin copolymers (A-4-5) and (A-4-6)obtained in Preparation Examples 13 and 14, a film having a thickness of30 μm was formed in the similar manner to that of Example 19.

Melt properties of the ethylene/α-olefin copolymers (A-4-5) and (A-4-6)and physical properties of the films formed from the copolymers are setforth in Table 16.

Comparative Example 8

The ethylene/α-olefin copolymer (A-4-1) obtained in Preparation Example9 and a high-pressure radical polymerization low-density polyethylene(D-2) shown in Table 15 were used to prepare an ethylene copolymercomposition in a manner similar to that of Example 19. From the ethylenecopolymer composition, a film having a thickness of 30 μm was formed ina manner similar to that of Example 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 15.

As is evident from Comparative Example 8 and Reference Example 12, evenby blending the ethylene/α-olefin copolymer with such a high-pressureradical polymerization low-density polyethylene as used in ComparativeExample 8, the film formed from the resulting composition was notincreased so much in the transparency.

Comparative Example 9

The ethylene/α-olefin copolymer (A-4-1) obtained in Preparation Example9 and a high-pressure radical polymerization low-density polyethylene(D-3) shown in Table 15 were used to prepare an ethylene copolymercomposition in a manner similar to that of Example 19. From the ethylenecopolymer composition, a film having a thickness of 30 μm was formed ina manner similar to that of Example 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 15.

As is evident from Comparative Example 9 and Reference Example 12, evenby blending the ethylene/α-olefin copolymer with such a high-pressureradical polymerization low-density polyethylene as used in ComparativeExample 9, the resulting composition was not hardly improved in the melttension, and the film formed from the composition was not increased somuch in the transparency.

It has been confirmed from the examples and the reference examplesdescribed above that when the ethylene/α-olefin copolymer is blendedwith a specific high-pressure radical polymerization low-densitypolyethylene, the resulting composition is improved in the melt tensionand in the haze (transparency). Further, it has been also confirmed thatthe ethylene copolymer composition of the invention is excellent in theblocking resistance.

                  TABLE 14                                                        ______________________________________                                        Ethylene/α-olefin copolymer                                             ______________________________________                                        Code               Amount of  Density                                                                              MFR                                      No.  Comonomer     comonomer  g/cm.sup.3                                                                           g/10 min                                 ______________________________________                                        A-4-1                                                                              1-hexene      2.8        0.923  1.1                                      A-4-2                                                                              1-hexene      3.0        0.920  2.4                                      A-4-3                                                                              1-hexene      2.6        0.920  2.3                                      A-4-4                                                                              4-methyl-1-pentene                                                                          2.4        0.920  2.0                                      A-4-5                                                                              1-hexene      2.8        0.922  2.0                                      A-4-6                                                                              1-hexene      1.9        0.927  0.9                                      C-5  1-hexene      3.6        0.922  1.0                                      ______________________________________                                                                     Decane-                                                      For-        For- soluble                                                                              For- Un-                                  Code Tm     mula   MT   mula portion                                                                              mula saturated                                                                            FI                            No.  °C.                                                                           (1)    g    (2)  weight %                                                                             (3)  bond*1 s.sup.-1                      ______________________________________                                        A-4-1                                                                              116.8  119.2  1.5  2.0  0.02   1.19 0.09   67                            A-4-2                                                                              114.8  118.0  0.7  1.1  0.25   1.57 0.07   150                           A-4-3                                                                              115.0  118.0  0.7  1.1  0.08   1.57 0.08   110                           A-4-4                                                                              114.7  118.0  0.8  1.2  0.19   1.57 0.12   100                           A-4-5                                                                              115.0  118.8  0.8  1.2  0.20   1.30 0.07   100                           A-4-6                                                                              115.0  120.8  1.8  2.4  0.14   1.01 0.06   58                            C-5  123.2  118.8  1.8  2.2  7.9    1.30 0.25   190                           ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d - 250 wherein Tm means a melting point at     the maximum peak of the DSC endothermic curve, and d means a density.         Formula (2): MT ≦ 2.2 × MFR.sup.-0.84 wherein MT means a mel     tension at 190° C., and MFR means a melt flow rate.                    Formula (3): W < 80 × exp(-100(d - 0.88)) + 0.1  under the conditio     of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (3): W < 80 × (MFR - 9).sup.-0.26 × exp(-100(d -          0.88)) + 0.1  under the condition of MFR > 10 g/10 min!, wherein W means      weight of a decanesoluble portion at 23° C.                            *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A4-1˜A4-6: Zr type catalyst, gas phase polymerization                   C5: Ti type catalyst, gas phase polymerization                           

                  TABLE 15                                                        ______________________________________                                        High-pressure radical polymerization low-density polyethylene                 MFR                      Physical property of film                            Code (g/10  Mw/              Density                                                                             Haze Gloss                                                                              Film impact                      No.  min)   Mn     *1   *2   (g/cm.sup.3)                                                                        %    %    kg · cm/cm              ______________________________________                                        B-4-1                                                                              5.2    9.4    17.8 4.3  0.919 15.0 14   1,050                            B-4-2                                                                              0.50   4.4    10.2 <0   0.924  7.4 51   1,750                            D-2  0.32   10.6   8.8  <0   0.922 --   --   --                               D-3  66     8.9    26.1 12.4 0.915 --   --   --                               ______________________________________                                         Remark:                                                                       *1: value obtained by the formula 7.5 × log(MFR) + 12.5                 *2: value obtained by the formula 7.5 × log(MFR) - 1.2             

                  TABLE 16                                                        ______________________________________                                                              Mixing  Melt property of                                Com-         Com-     ratio   ethylene copolymer                              ponent       ponent   A/B     composition                                             A        B        weight                                                                              MFR    MT   FI                                        Code No. Code No. ratio g/10 min.                                                                            g    s.sup.-1                          ______________________________________                                        Ex. 19  A-4-1    B-4-2    90/10 0.9    4.3  90                                Ex. 20  A-4-1    B-4-2    75/25 0.8    6.8  120                               Ex. 21  A-4-1    B-4-1    90/10 1.1    3.6  100                               Ref. Ex. 12                                                                           A-4-1             100/0 1.1    1.5  67                                Comp. Ex. 6                                                                           C-5      B-4-1    90/10 1.0    4.0  245                               Comp. Ex. 7                                                                           C-5               100/0 1.0    1.8  190                               Ex. 22  A-4-2    B-4-1    90/10 2.4    1.8  200                               Ref. Ex. 13                                                                           A-4-2             100/0 2.4    0.7  150                               Ex. 23  A-4-3    B-4-1    90/10 2.4    1.8  150                               Ref. Ex. 14                                                                           A-4-3             100/0 2.3    0.7  110                               Ex. 24  A-4-4    B-4-1    90/10 2.0    2.1  135                               Ref. Ex. 15                                                                           A-4-4             100/0 2.0    0.8  100                               Ex. 25  A-4-5    B-4-1    90/10 2.0    2.2  130                               Ref. Ex. 16                                                                           A-4-5             100/0 2.0    0.8  100                               Ex. 26  A-4-6    B-4-1    90/10 0.9    4.5  85                                Ref. Ex. 17                                                                           A-4-6             100/0 0.9    1.8  58                                Comp. Ex. 8                                                                           A-4-1    D-2      90/10 0.9    6.6  70                                Ref. Ex. 12                                                                           A-4-1             100/0 1.1    1.5  67                                Comp. Ex. 9                                                                           A-4-1    D-3      90/10 1.3    1.6  130                               Ref. Ex. 12                                                                           A-4-1             100/0 1.1    1.5  67                                ______________________________________                                        Physical property of film                                                                                          Block-                                                  Haze          Film    ing   Mold-                                      Haze   Enhancing                                                                              Gloss                                                                              impact  force ability                                    %      rate     %    kg · cm/cm                                                                   g/cm  *2                                 ______________________________________                                        Ex. 19  2.8    30       180  4,210   0.19  AA                                 Ex. 20  2.4    27       112  4,050   0.30  AA                                 Ex. 21  3.2    36       96   3,910   0.24  AA                                 Ref. Ex. 12                                                                           8.8    100      62   7,750   0.11  CC                                 Comp. Ex. 6                                                                           6.2    54       95   2,760   4.7   AA                                 Comp. Ex. 7                                                                           11.5   100      44   3,400   4.0   CC                                 Ex. 22  2.8    31       99   3,960   0.26  CC                                 Ref. Ex. 13                                                                           9.0    100      58   7,600   0.18  CC                                 Ex. 23  3.0    34       102  2,920   0.42  CC                                 Ref. Ex. 14                                                                           8.8    100      60   5,600   0.25  CC                                 Ex. 24  3.0    34       100  3,100   0.11  BB                                 Ref. Ex. 15                                                                           8.9    100      60   6,700   0.09  CC                                 Ex. 25  3.2    35       96   3,900   0.20  BB                                 Ref. Ex. 16                                                                           9.2    100      56   7,700   0.15  CC                                 Ex. 26  3.4    43       94   4,230   0     AA                                 Ref. Ex. 17                                                                           8.0    100      73   8,100   0     CC                                 Comp. Ex. 8                                                                           7.8    89       63   4,260   0.15  AA                                 Ref. Ex. 12                                                                           8.8    100      62   7,750   0.11  CC                                 Comp. Ex. 9                                                                           8.0    91       87   3,350   0.12  CC                                 Ref. Ex. 12                                                                           8.8    100      62   7,750   0.11  CC                                 ______________________________________                                         Remark:                                                                       Haze enhancing rate *1: haze of a film formed from the ethylene copolymer     composition based on the haze of a film formed from only the                  ethylene/olefin copolymer (i.e., copolymer of each reference example,         copolymer of each comparative example) being 100. As this value is            smaller, the haze is more improved.                                           Moldability *2: AA: MT ≧ 3, BB: 3 > MT ≧ 2, CC: 2 > MT     

Preparation Example 15 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

6.3 kg of silica having been dried at 250° C. for 10 hours was suspendedin 100 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=0.96 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 60 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 15 liters of a toluene solution ofbis(n-butylcyclopentadienyl)zirconium dichloride (Zr=42.7 mmol/l) at 30°C. over 30 minutes, and the reaction was further carried out at 30° C.for 2 hours. Then, the supernatant liquid was removed, and the residuewas washed twice with hexane to obtain a solid catalyst containing 6.2mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 300 liters of hexane containing 14 mol of triisobutylaluminum wasadded 8.5 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 7 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 10 g based on 1 g of the solidcatalyst.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 18 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.15 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thepolymerizer (gas composition: 1-hexene/ethylene=0.020,hydrogen/ethylene=6.6×10⁻⁴, ethylene concentration=16%).

Thus, an ethylene/α-olefin copolymer (A-4-7) was obtained in an amountof 5.0 kg/hour. The copolymer had a density of 0.923 g/cm³ and a meltflow rate (MFR) of 1.1 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 116.8° C. Further,the copolymer had a melt tension (MT) of 1.5 g. The amount of thedecane-soluble portion in the copolymer was 0.02 part by weight at 23°C. The number of unsaturated bond in the copolymer was 0.09 per 1,000carbon atoms, and was 0.16 per one molecule of the polymer. The B valueindicating the α-olefin distribution in the copolymer chain was 1.02.

Physical properties of the ethylene/α-olefin copolymer (A-4-7) are setforth in Table 17.

Reference Example 18

Film formation!

The ethylene/α-olefin copolymer (A-4-7) obtained in Preparation Example15 was subjected to inflation by the use of a single-screw extruder (20mmφ·L/D=26) equipped with a die of 25 mmφ (lip width: 0.7 mm) and asingle-slit air ring under the conditions of an air flow rate of 90l/min, an extrusion rate of 9 g/min, a blow ratio of 1.8, a take-up rateof 2.4 m/min and a processing temperature of 200° C., to form a filmhaving a thickness of 30 μm.

Melt properties of the ethylene/α-olefin copolymer (A-4-7) and physicalproperties of the film formed from the copolymer are set forth in Table19.

Example 27

Preparation of a composition!

The ethylene/α-olefin copolymer (A-4-7) obtained in Preparation Example15 and a crystalline polyolefin (B-2-6) shown in Table 18 were dryblended in a weight ratio of 90/10 (A-4-7)/(B-2-6)!. To the resultantblend were added 0.05 part by weight oftri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1 partby weight of n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionateas a heat-resistant stabilizer and 0.05 part by weight of calciumstearate as a hydrochloric acid absorbent, each based on 100 parts byweight of the resin. Then, the resultant mixture was kneaded by aconical-tapered twin-screw extruder (produced by Haake BuchlerInstrument Inc.) at a preset temperature of 180° C., to obtain anethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 18.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 19.

As compared with Reference Example 18, the ethylene copolymercomposition obtained above was improved in the flow index (FI) withinthe high-shear region, and the film formed from the composition wasincreased in the transparency and the rigidity.

Example 28

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 27 was repeated except for using the ethylene/α-olefin copolymer(A-4-7) obtained in Preparation Example 15 and a crystalline polyolefin(B-2-7) shown in Table 18 in a mixing ratio of 90/10 (A-4-7)/(B-2-7)!,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 18.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 19.

As compared with Reference Example 18, the ethylene copolymercomposition obtained above was improved in the flow index (FI) withinthe high-shear region, and the film formed from the composition wasincreased in the rigidity.

Example 29

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 27 was repeated except for using the ethylene/α-olefin copolymer(A-4-7) obtained in Preparation Example 15 and a crystalline polyolefin(B-2-8) shown in Table 18 in a mixing ratio of 90/10 (A-4-7)/(B-2-8)!,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 18.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 19.

As compared Reference Example 18, the ethylene copolymer compositionobtained above was improved in the flow index (FI) within the high-shearregion, and the film formed from the composition was increased in therigidity.

Example 30

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 27 was repeated except for using the ethylene/α-olefin copolymer(A-4-7) obtained in Preparation Example 15 and a crystalline polyolefin(B-2-9) shown in Table 18 in a mixing ratio of 90/10 (A-4-7)/(B-2-9)!,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 18.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 19.

As compared with Reference Example 18, the ethylene copolymercomposition obtained above was improved in the flow index (FI) withinthe high-shear region, and the film formed from the composition wasincreased in the rigidity.

Example 31

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 27 was repeated except for using the ethylene/α-olefin copolymer(A-4-7) obtained in Preparation Example 15 and a crystalline polyolefin(B-2-10) shown in Table 18 in a mixing ratio of 90/10 (A-4-7)/(B-2-10)!,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 18.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 19.

As compared with Reference Example 18, the ethylene copolymercomposition obtained above was improved in the flow index (FI) withinthe high-shear region, and the film formed from the composition wasincreased in the rigidity.

                  TABLE 17                                                        ______________________________________                                        Code                 Amount of  Density                                                                             MFR                                     No.        Comonomer comonomer  g/cm.sup.3                                                                          g/10 min                                ______________________________________                                        A-4-7      1-hexene  2.8        0.923 1.1                                     ______________________________________                                                                     Decane-                                                      For-        For- soluble                                                                              For- Un-                                  Code Tm     mula   MT   mula portion                                                                              mula saturated                                                                            FI                            No.  °C.                                                                           (1)    g    (2)  weight %                                                                             (3)  bond*1 s.sup.-1                      ______________________________________                                        A-4-7                                                                              116.8  119.2  1.5  2.0  0.02   1.19 0.09   67                            ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d - 250 wherein Tm means the maximum peak       temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT ≦ 2.2 × MFR.sup.-0.84 wherein MT means a mel     tension at 190° C., and MFR means a melt flow rate.                    Formula (3): W < 80 × exp(-100(d - 0.88)) + 0.1  under the conditio     of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (3): W < 80 × (MFR - 9).sup.-0.26 × exp(-100(d -          0.88)) + 0.1  under the condition of MFR > 10 g/10 min!, wherein W means      weight of a decanesoluble portion at 23° C.                            *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A4-7: Zr type catalyst, gas phase polymerization                         

                  TABLE 18                                                        ______________________________________                                        Code   Composition (mol %) MFR      Density                                   No.    Ethylene  Propylene                                                                              Butene (g/10 min)                                                                           (g/cm.sup.3)                          ______________________________________                                        B-2-6  100       --       --     5.0    0.968                                 B-2-7  99.8      --       0.2    0.65   0.963                                 B-2-8  3.4       95.0     1.6    6.8    0.910                                 B-2-9  --        100      --     6.5    0.910                                  B-2-10                                                                              --        --       100    2.0    0.908                                 ______________________________________                                         Remark:                                                                       MFR measuring temperature                                                     B2-6, B2-7: 190° C.                                                    B2-8˜B2-10: 230° C.                                         

                  TABLE 19                                                        ______________________________________                                                              Mixing                                                  Com-         Com-     ratio                                                   ponent       ponent   A/B     Melt property                                           A        B        weight                                                                              MFR    MT   FI                                        Code No. Code No. ratio g/10 min                                                                             g    s.sup.-1                          ______________________________________                                        Ref. Ex. 18                                                                           A-4-7    --       100/0 1.1    1.5  67                                Ex. 27  A-4-7    B-2-6    90/10 1.3    1.5  86                                Ex. 28  A-4-7    B-2-7    90/10 1.0    1.9  90                                Ex. 29  A-4-7    B-2-8    90/10 1.1    1.5  152                               Ex. 30  A-4-7    B-2-9    90/10 1.1    1.6  99                                Ex. 31  A-4-7     B-2-10  90/10 1.1    1.5  127                               ______________________________________                                        Physical property of film                                                     Haze       Tensile test (MD)                                                                            Tensile test (TD)                                           %      YM kg/cm.sup.2                                                                           EL %  YM kg/cm.sup.2                                                                         EL %                                 ______________________________________                                        Ref. Ex. 18                                                                           8.8    2,900      550   3,100    640                                  Ex. 27  6.7    3,700      580   4,900    620                                  Ex. 28  9.3    3,600      590   4,700    680                                  Ex. 29  8.8    4,800      560   6,300    600                                  Ex. 30  9.0    5,100      560   6,900    580                                  Ex. 31  12.0   3,100      550   3,500    640                                  ______________________________________                                    

Preparation Example 16 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

6.3 kg of silica having been dried at 250° C. for 10 hours was suspendedin 100 liters of toluene, and the resultant suspension was cooled to 0°C. Thereafter, to the suspension was dropwise added 41 liters of atoluene solution of methylaluminoxane (Al=0.96 mol/l) over 1 hour.During the addition, the temperature of the system was kept at 0° C.Successively, the reaction was carried out at 0° C. for 60 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 4hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 125 liters of toluene. To the reaction systemwas dropwise added 15 liters of a toluene solution ofbis(n-butylcyclopentadienyl)zirconium dichloride (Zr=42.7 mmol/l) at 30°C. over 30 minutes, and the reaction was further carried out at 30° C.for 2 hours. Then, the supernatant liquid was removed, and the residuewas washed twice with hexane to obtain a solid catalyst containing 6.2mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 300 liters of hexane containing 14 mol of triisobutylaluminum wasadded 8.5 kg of the solid catalyst obtained in the above, and theresultant mixture was subjected to prepolymerization with ethylene at35° C. for 7 hours to obtain a prepolymerized catalyst in whichpolyethylene was present in an amount of 10 g based on 1 g of the solidcatalyst.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 18 kg/cm² -G and apolymerization temperature of 80° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.15 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thepolymerizer (gas composition: 1-hexene/ethylene=0.020,hydrogen/ethylene=6.6×10⁴, ethylene concentration=16%).

Thus, an ethylene/α-olefin copolymer (A-4-8) was obtained in an amountof 5.0 kg/hour. The copolymer had a density of 0.923 g/cm³ and a meltflow rate (MFR) of 1.1 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 116.8° C. Further,the copolymer had a melt tension (MT) of 1.5 g. The amount of thedecane-soluble portion in the copolymer was 0.02 part by weight at 23°C. The number of unsaturated bond in the copolymer was 0.09 per 1,000carbon atoms, and was 0.16 per one molecule of the polymer. The B valueindicating the α-olefin distribution in the copolymer chain was 1.02.

Physical properties of the ethylene/α-olefin copolymer (A-4-8) are setforth in Table 20.

Reference Example 19

Film formation!

The ethylene/α-olefin copolymer (A-4-8) prepared in Preparation Example16 was subjected to inflation by the use of a single-screw extruder (20mmφ·L/D=26) equipped with a die of 25 mmφ (lip width: 0.7 mm) and asingle-slit air ring under the conditions of an air flow rate of 90l/min, an extrusion rate of 9 g/min, a blow ratio of 1.8, a take-up rateof 2.4 m/min and a processing temperature of 200° C., to form a filmhaving a thickness of 30 μm. Melt properties of the ethylene/α-olefincopolymer (A-4-8) and physical properties of the film formed from thecopolymer are set forth in Table 22.

Example 32

Preparation of a composition!

The ethylene/α-olefin copolymer (A-4-8) obtained in Preparation Example16 and an olefin type elastomer (B-3-4) (density: 0.89 g/cm³) shown inTable 21 were dry blended in a weight ratio of 90/10 (A-4-8)/(B-3-4)!.To the resultant blend were added 0.05% by weight oftri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1% byweight of n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate asa heat-resistant stabilizer and 0.05% by weight of calcium stearate as ahydrochloric acid absorbent, each based on 100 parts by weight of theresin. Then, the resultant mixture was kneaded by a conical-taperedtwin-screw extruder (produced by Haake Buchler Instrument Inc.) at apreset temperature of 180° C., to obtain an ethylene copolymercomposition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation in a manner similar to that of Reference Example 19, toform a film having a thickness of 30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 22.

As compared with Reference Example 19, the ethylene copolymercomposition obtained above was improved in the moldability (MT, FI), andthe film formed from the composition was increased in the transparencyand the film impact.

Example 33

Preparation of a composition!

The procedure for preparing the ethylene copolymer composition inExample 32 was repeated except for using the ethylene/α-olefin copolymer(A-4-8) obtained in Preparation Example 16 and an olefin type elastomer(B-3-5) shown in Table 21 in a weight ratio of 90/10 (A-4-8)/(B-3-5)!,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofReference Example 19.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 22.

As compared with Reference Example 19, the ethylene copolymercomposition obtained above was improved in the moldability (MT, FI), andthe film formed from the composition was increased in the transparencyand the film impact.

                  TABLE 20                                                        ______________________________________                                        Code                 Amount of  Density                                                                             MFR                                     No.        Comonomer comonomer  g/cm.sup.3                                                                          g/10 min                                ______________________________________                                        A-4-8      1-hexene  2.8        0.923 1.1                                     ______________________________________                                                                     Decane-                                                      For-        For- soluble                                                                              For- Un-                                  Code Tm     mula   MT   mula portion                                                                              mula saturated                                                                            FI                            No.  °C.                                                                           (1)    g    (2)  weight %                                                                             (3)  bond*1 s.sup.-1                      ______________________________________                                        A-4-8                                                                              116.8  119.2  1.5  2.0  0.02   1.19 0.09   67                            ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d - 250 wherein Tm means the maximum peak       temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT ≦ 2.2 × MFR.sup.-0.84 wherein MT means a mel     tension at 190° C., and MFR means a melt flow rate.                    Formula (3): W < 80 × exp(-100(d - 0.88)) + 0.1  under the conditio     of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at 23° C.                                                      Formula (3): W < 80 × (MFR - 9).sup.-0.26 × exp(-100(d -          0.88)) + 0.1  under the condition of MFR > 10 g/10 min!, wherein W means      weight of a decanesoluble portion at 23° C.                            *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A4-8: Zr type catalyst, gas phase polymerization                         

                  TABLE 21                                                        ______________________________________                                        Code  Composition (mol %)  MFR      Density                                   No.   Ethylene Propylene                                                                              Butene                                                                              ENB  (g/10 min)                                                                           (g/cm.sup.3)                        ______________________________________                                        B-3-4 88       --       10    2    1.5    0.89                                B-3-5 74       24       --    2    0.2    0.87                                ______________________________________                                         Remark: ENB: ethylidene norbornene                                       

                  TABLE 22                                                        ______________________________________                                                  Mixing            Physical property                                           ratio Melt property                                                                             of film                                                           A/B     MFR                Film                               Code     Code   weight  g/10 MT   FI  Haze impact                             No.      No.    ratio   min  g    s.sup.-1                                                                          %    kg · cm/cm                ______________________________________                                        Ref.  A-4-8  --     100/0 1.1  1.5  67  8.8  7,750                            Ex. 19                                                                        Ex. 32                                                                              A-4-8  B-3-4  90/10 1.1  4.0  78  3.5  NB                                                                            (>8500)                          Ex. 33                                                                              A-4-8  B-3-5  90/10 1.0  3.6  73  4.0  NB                                                                            (>8500)                          ______________________________________                                         Remark: NB means that the film is not broken. (8,500 kg · cm/cm      measurable maximum film impact)                                          

Preparation Example 17 Preparation of an ethylene/α-olefin copolymer

Preparation of a solid catalyst!

10.0 kg of silica having been dried at 250° C. for 10 hours wassuspended in 154 liters of toluene, and the resultant suspension wascooled to 0° C. Thereafter, to the suspension was dropwise added 57.5liters of a toluene solution of methylaluminoxane (Al=1.33 mol/l) over 1hour. During the addition, the temperature of the system was kept at 0°C. Successively, the reaction was carried out at 0° C. for 30 minutes.Then, the temperature of the system was elevated to 95° C. over 1.5hours, and the reaction was carried out at the same temperature for 20hours. Thereafter, the temperature of the system was lowered to 60° C.,and the supernatant liquid was removed by decantation.

The solid component obtained above was washed twice with toluene, andthen again suspended in 100 liters of toluene. To the reaction systemwas dropwise added 16.8 liters of a toluene solution ofbis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride (Zr=27.0mmol/l) at 80° C. over 30 minutes, and the reaction was further carriedout at 80° C. for 2 hours. Then, the supernatant liquid was removed, andthe residue was washed twice with hexane to obtain a solid catalystcontaining 3.5 mg of zirconium based on 1 g of the solid catalyst.

Preparation of a prepolymerized catalyst!

To 87 liters of hexane containing 2.5 mol of triisobutylaluminum wereadded 870 g of the solid catalyst obtained in the above and 260 g of1-hexene, and the resultant mixture was subjected to prepolymerizationwith ethylene at 35° C. for 5 hours to obtain a prepolymerized catalystin which polyethylene was present in an amount of 10 g based on 1 g ofthe solid catalyst.

Polymerization!

In a continuous fluidized bed gas phase reactor, ethylene wascopolymerized with 1-hexene at a total pressure of 18 kg/cm² -G and apolymerization temperature of 75° C. To the reactor were continuouslyfed the prepolymerzied catalyst prepared in the above at a feed rate of0.15 mmol/hour in terms of zirconium atom and triisobutylaluminum at afeed rate of 10 mmol/hour while continuously feeding ethylene, 1-hexene,hydrogen and nitrogen to maintain a constant gas composition in thepolymerizer (gas composition: 1-hexene/ethylene=0.034,hydrogen/ethylene=1.7×10⁻⁴, ethylene concentration=20%).

Thus, an ethylene/α-olefin copolymer (A-5-1) was obtained in an amountof 5.8 kg/hour. The copolymer had a density of 0.908 g/cm³ and a meltflow rate (MFR) of 0.77 g/10 min. The temperature at the maximum peak ofthe DSC endothermic curve (Tm) of the copolymer was 93.6° C. The amountof the decane-soluble portion in the copolymer was 0.51% by weight at23° C. The number of unsaturated bond in the copolymer was 0.08 per1,000 carbon atoms, and was 0.70 per one molecule of the polymer.

Physical properties of the ethylene/α-olefin copolymer (A-5-1) are setforth in Table 23.

Example 34

Preparation of an ethylene/α-olefin copolymer composition!

The ethylene/α-olefin copolymer (A-5-1) (density: 0.908 g/cm³) obtainedin Preparation Example 17 and an ethylene/α-olefin copolymer (A-6-1)(density: 0.938 g/cm³) prepared in the same manner as described inPreparation Example 17 except for adjusting the comonomer amount to thatset forth in Table 23 were melt kneaded in a weight ratio of 60/40(A-5-1)/(A-6-1)!, to obtain an ethylene/α-olefin copolymer composition(L-2-1).

Physical properties of the ethylene/α-olefin copolymer (A-6-1) are setforth in Table 23, and physical properties of the ethylene/α-olefincopolymer composition (L-2-1) are set forth in Table 24.

Preparation of an ethylene copolymer composition!

The ethylene/α-olefin copolymer composition (L-2-1) and a high-pressureradical polymerization low-density polyethylene (B-4-3) shown in Table25 were dry blended in a mixing ratio of 90/10 (L-2-1)/(B-4-3)!. To theresultant blend were added 0.05 part by weight oftri(2,4-di-t-butylphenyl)phosphate as a secondary antioxidant, 0.1 partby weight of n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionateas a heat-resistant stabilizer and 0.05 part by weight of calciumstearate as a hydrochloric acid absorbent, each based on 100 parts byweight of the resin. Then, the resultant mixture was kneaded by aconical-tapered twin-screw extruder (produced by Haake BuchlerInsturment Inc.) at a preset temperature of 180° C., to obtain anethylene copolymer composition.

Film formation!

The ethylene copolymer composition obtained in the above was subjectedto inflation by the use of a single-screw extruder (20 mmφ·L/D=26)equipped with a die of 25 mmφ (lip width: 0.7 mm) and a single-slit airring under the conditions of an air flow rate of 90 l/min, an extrusionrate of 9 g/min, a blow ratio of 1.8, a take-up rate of 2.4 m/min and aprocessing temperature of 200° C., to form a film having a thickness of30 μm.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 26.

From the ethylene/α-olefin copolymer composition (L-2-1) prepared inPreparation Example 17, a film having a thickness of 30 μm was formed ina manner similar to that of Example 34.

Melt properties of the ethylene/α-olefin copolymer composition (L-2-1)and physical properties of the film formed from the composition are setforth in Table 26.

As is evident from Example 34 and Reference Example 20, theethylene/α-olefin copolymer composition was increased in the melttension and the flow index within the high-shear region by blending itwith a high-pressure radical polymerization low-density polyethylene,and the film formed from the composition containing the polyethylene wasenhanced in the transparency.

Example 35

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (A-5-2) (density: 0.909 g/cm³) and anethylene/α-olefin copolymer (A-6-2) (density: 0.943 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 17 except for adjusting the comonomer amount to thatset forth in Table 23, were melt kneaded in a weight ratio of 70/30(A-5-2)/(A-6-2)!, to obtain an ethylene/α-olefin copolymer composition(L-2-2).

Physical properties of the ethylene/α-olefin copolymers (A-5-2) and(A-6-2) are set forth in Table 23, and physical properties of theethylene/α-olefin copolymer composition (L-2-2) are set forth in Table24.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 34 was repeated except for using the ethylene/α-olefin copolymercomposition (L-2-2), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 34.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 26.

Reference Example 21

Film formation!

From the ethylene/α-olefin copolymer composition (L-2-2) prepared inExample 35, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 34.

Melt properties of the ethylene/α-olefin copolymer composition (L-2-2)and physical properties of the film formed from the composition are setforth in Table 26.

As is evident from Example 35 and Reference Example 21, theethylene/α-olefin copolymer composition was increased in the melttension and the flow index within the high-shear region by blending itwith a high-pressure radical polymerization low-density polyethylene,and the film formed from the composition containing the polyethylene wasenhanced in the transparency.

Example 36

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (A-5-3) (density: 0.910 g/cm³) and anethylene/α-olefin copolymer (A-6-3) (density: 0.946 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 17 except for adjusting the comonomer amount to thatset forth in Table 23, were melt kneaded in a weight ratio of 60/40(A-5-3)/(A-6-3)!, to obtain an ethylene/α-olefin copolymer composition(L-2-3).

Physical properties of the ethylene/α-olefin copolymers (A-5-3) and(A-6-3) are set forth in Table 23, and physical properties of theethylene/α-olefin copolymer composition (L-2-3) are set forth in Table24.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 34 was repeated except for using the ethylene/α-olefin copolymercomposition (L-2-3), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 34.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 26.

Reference Example 22

Film formation!

From the ethylene/α-olefin copolymer composition (L-2-3) prepared inExample 36, a film having a thickness of 30 μm was formed in a mannersimilar to that of Example 34.

Melt properties of the ethylene/α-olefin copolymer composition (L-2-3)and physical properties of the film formed from the composition are setforth in Table 26.

As is evident from Example 36 and Reference Example 22, theethylene/α-olefin copolymer composition was increased in the melttension and the flow index within the high-shear region by blending itwith a high-pressure radical polymerization low-density polyethylene,and the film formed from the composition containing the polyethylene wasenhanced in the transparency.

Comparative Example 10

Preparation of an ethylene/α-olefin copolymer composition!

An ethylene/α-olefin copolymer (C-6) (density: 0.915 g/cm³) and anethylene/α-olefin copolymer (C-7) (density: 0.933 g/cm³), each of saidcopolymers having been prepared in the same manner as described inPreparation Example 17 except for replacing the zirconium catalystsystem with a titanium type catalyst system described in Japanese PatentPublication No. 63(1988)-54289, and varying the gas composition to thatshown in Table 23, were melt kneaded in a weight ratio of 60/40(C-6)/(C-7)!, to obtain an ethylene/α-olefin copolymer composition(L-2-4). Physical properties of the ethylene/α-olefin copolymercomposition (L-2-4) are set forth in Table 24.

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 34 was repeated except for using the ethylene/α-olefin copolymercomposition (L-2-4), to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition obtained in the above, a filmhaving a thickness of 30 μm was formed in a manner similar to that ofExample 34.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 26.

The film obtained above was inferior in the transparency and the filmimpact to the film of Example 34 formed from the ethylene/α-olefincopolymer composition (L-2-1) having almost the same density and MFR.

Comparative Example 11

From the ethylene/α-olefin copolymer composition (L-2-4) obtained inComparative Example 10, a film having a thickness of 30 μm was formed ina manner similar to that of Example 34.

Melt properties of the ethylene/α-olefin copolymer composition (L-2-4)and physical properties of the film formed from the composition are setforth in Table 26.

It was confirmed from Comparative Example 10 and Comparative Example 11that the film of Comparative Example 10 was less increased in thetransparency as compared with the film of Example 34.

Comparative Example 12

Preparation of an ethylene copolymer composition!

The procedure for preparing the ethylene copolymer composition inExample 34 was repeated except for using an ethylene/a-olefin copolymer(C-8) prepared in the same manner as described in Preparation Example 17except for adjusting the comonomer amount to that set forth in Table 23,to prepare an ethylene copolymer composition.

Film formation!

From the ethylene copolymer composition, a film having a thickness of 30μm was formed in a manner similar to that of Example 34.

Melt properties of the ethylene copolymer composition and physicalproperties of the film formed from the composition are set forth inTable 26.

The ethylene copolymer composition obtained in Comparative Example 12was inferior in the flow index within the high-shear region to theethylene copolymer composition of Example 36 having almost the same MFR.Further, the film obtained in Comparative Example 12 was inferior in thefilm impact to the film formed from the ethylene copolymer compositionof Example 34 using the ethylene/α-olefin copolymer composition (L-2-1)having almost the same density and MFR as those of the ethylene/α-olefincopolymer (C-8).

                  TABLE 23                                                        ______________________________________                                                      Amount         MFR                                              Code Co-      of co-   Density                                                                             g/10   η!                                                                            Tm   Formula                          No.  monomer  monomer  g/cm3 min   g/dl °C.                                                                         (1)                              ______________________________________                                        A-5-1                                                                              1-hexene 4.8      0.908 0.77  1.94 93.6 113.2                            A-5-2                                                                              1-hexene 4.7      0.909 0.46  2.14 97.4 113.6                            A-5-3                                                                              1-hexene 4.8      0.910 0.60  2.03 96.8 114.0                            C-6  1-hexene 6.1      0.915 0.65  2.00 120.3                                                                              116.0                            A-6-1                                                                              1-hexene 1.4      0.938 13.0  1.12 118.2                                                                              125.2                            A-6-2                                                                              1-hexene 1.0      0.943 229   0.64 118.9                                                                              127.2                            A-6-3                                                                              1-hexene 1.0      0.946 240   0.64 119.5                                                                              128.4                            C-7  1-hexene 2.8      0.933 19.2  1.04 128.0                                                                              123.2                            C-8  1-hexene 2.8      0.922 2.0   1.61 115.0                                                                              118.8                            ______________________________________                                                            Decane-soluble                                            Code MT     Formula portion  Formula                                                                             Unsaturated                                                                           FI                                 No.  g      (2)     weight % (3)   bond*1  s.sup.-1                           ______________________________________                                        A-5-1                                                                              2.4    2.7     0.51     5.0   0.08    50                                 A-5-2                                                                              3.8    4.2     0.48     4.5   0.05    30                                 A-5-3                                                                              2.7    3.4     0.49     4.1   0.09    33                                 C-6  2.8    3.2     13.50    2.5   0.23    140                                A-6-1                                                                              0.1>   --      0.32     0.45  0.15    980                                A-6-2                                                                              0.1>   --      0.45     0.70  0.09    17760                              A-6-3                                                                              0.1>   --      0.40     0.55  0.10    22300                              C-7  0.1>   --      2.20     0.83  0.28    1480                               C-8  0.8    1.2     0.20     1.30  0.07    100                                ______________________________________                                         Remark:                                                                       Formula (1): Tm < 400 × d - 250 wherein Tm means the maximum peak       temperature of the DSC endothermic curve, and d means a density.              Formula (2): MT ≦ 2.2 × MFR.sup.-0.84 wherein MT means a mel     tension at 190° C., and MFR means a melt flow rate.                    Formula (3): W < 80 × exp(-100(d - 0.88)) + 0.1  under the conditio     of MFR ≦ 10 g/10 min!, wherein W means a weight of a decanesoluble     portion at room temperature.                                                  Formula (3): W < 80 × (MFR - 9).sup.-0.26 × exp(-100(d -          0.88)) + 0.1  under the condition of MFR > 10 g/10 min!, wherein W means      weight of a decanesoluble portion at room temperature.                        *1: the number of unsaturated bond in the ethylene/olefin copolymer based     on 1,000 carbon atoms.                                                        A5-1˜A5-3, A6-1˜A6-3, C8: Zr type catalyst, gas phase             polymerization                                                                C6, C7: Ti type catalyst, gas phase polymerization                       

                  TABLE 24                                                        ______________________________________                                        Com-     Com-    Mixing                                                       ponent   ponent  ratio                                                        A        B       A/B           Melt property                                  Code     Code    (weight Density                                                                             MFR    MT    FI                                No.      No.     ratio)  g/cm.sup.3                                                                          g/10 min                                                                             g     s.sup.-1                          ______________________________________                                        L-2-1                                                                              A-5-1   A-6-1   60/40 0.921 2.0    1.0   170                             L-2-2                                                                              A-5-2   A-6-2   70/30 0.920 1.3    1.6   150                             L-2-3                                                                              A-5-3   A-6-3   60/40 0.924 2.3    0.8   360                             L-2-4                                                                              C-6     C-7     60/40 0.922 2.0    1.0   360                             ______________________________________                                    

                  TABLE 25                                                        ______________________________________                                        High-pressure radical polymerization low-density polyethylene                 (Component B)                                                                 MFR                      Physical property of film                            Code (g/10                   Density                                                                             Haze Gloss                                                                              Film impact                      No.  min)   Mw/Mn   *1   *2  (g/cm.sup.3)                                                                        %    %    kg · cm/cm              ______________________________________                                        B-4-3                                                                              0.50   4.4     10.2 <0  0.924 7.4  51   1,750                            ______________________________________                                         Remark:                                                                       *1: value obtained by the formula 7.5 × log(MFR) + 12.5                 *2: value obtained by the formula 7.5 × log(MFR) - 1.2             

                  TABLE 26                                                        ______________________________________                                                              Mixing                                                  Com-         Com-     ratio                                                   ponent       ponent   I/II    Melt property                                           I        II       weight                                                                              MFR    MT   FI                                        Code No. Code No. ratio g/10 min                                                                             g    s.sup.-1                          ______________________________________                                        Ex. 34  L-2-1    B-4-3    90/10 1.8    2.5  190                               Ref. Ex. 20                                                                           L-2-1    --       100/0 2.0    1.0  170                               Ex. 35  L-2-2    B-4-3    90/10 1.2    3.2  170                               Ref. Ex. 21                                                                           L-2-2    --       100/0 1.3    1.6  150                               Ex. 36  L-2-3    B-4-3    90/10 2.0    2.1  380                               Ref. Ex. 22                                                                           L-2-3    --       100/0 2.3    0.8  360                               Comp.   L-2-4    B-4-3    90/10 1.8    2.3  370                               Ex. 10                                                                        Comp.   L-2-4    --       100/0 2.0    1.0  360                               Ex. 11                                                                        Comp.   C-8      B-4-3    90/10 2.0    2.2  130                               Ex. 12                                                                        ______________________________________                                        Physical property of film                                                             Haze   Film impact                                                                              Blocking force                                                                          Moldability                                       %      kg · cm/cm                                                                      g/cm      *2                                        ______________________________________                                        Ex. 34  5.2    6,200      0         BB                                        Ref. Ex. 20                                                                           25.9   NB         0         CC                                                       (>8,500)                                                       Ex. 35  6.3    NB         0         AA                                                       (>8,500)                                                       Ref. Ex. 21                                                                           18.7   NB         0         CC                                                       (>8,500)                                                       Ex. 36  6.1    4,600      0         BB                                        Ref. Ex. 22                                                                           30.8   6,730      0         CC                                        Comp.   11.5   2,820      6.7       BB                                        Ex. 10                                                                        Comp.   26.8   3,500      5.6       CC                                        Ex. 11                                                                        Comp.   3.2    3,900      0.2       BB                                        Ex. 12                                                                        ______________________________________                                         Remark:                                                                       *1: NB means that the film is not broken. (8,500 kg · cm/cm =        measurable maximum film impact)                                               Moldability *2: AA: MT ≧ 3, BB: 2 ≦ MT < 3, CC: MT < 2     

What is claimed is:
 1. An ethylene copolymer compositioncomprising:(A-1) an ethylene/α-olefin copolymer of ethylene with anα-olefin of 3 to 20 carbon atoms having such properties that(i) thedensity (d) is in the range of 0.880 to 0.960 g/cm³, (ii) the melt flowrate (MFR) at 190° C. under a load of 2.16 kg is in the range of 0.01 to200 g/10 min, (iii) the temperature (Tm(°C.)) at which the endothermiccurve of said copolymer measured by a differential scanning calorimeter(DSC) shows the maximum peak and the density (d) satisfy the relation

    Tm<400×d-250,

(iv) the melt tension (MT(g)) at 190° C. and the melt flow rate (MFR)satisfy the relation

    MT>2.2×MFR.sup.-0.84,

(v) the flow index (FI(1/sec)) defined by a shear rate which is givenwhen a shear stress of molten copolymer at 190° C. reaches 2.4×10⁶dyne/cm² and the melt flow rate (MFR) satisfy the relation

    FI>75×MFR, and

(vi) the amount (W(% by weight)) of a decane-soluble portion at 23° C.and the density (d) satisfy the relation,in the case of MFR≦10 g/10 min,

    W<80×exp (-100(d-0.88))+0.1;

in the case of MFR>10 g/10 min,

    W<80×(MFR-9).sup.0.26 ×exp (-100(d-0.88))+0.1;

and (B-1) a high-pressure radical polymerization low-densitypolyethylene having such properties that(i) the melt flow rate (MFR) isin the range of 0.1 to 50 g/10 min, and (ii) the molecular weightdistribution (Mw/Mn, Mw=weight-average molecular weight,Mn=number-average molecular weight) measured by GPC and the melt flowrate (MFR) satisfy the relation

    Mw/Mn≧7.5×log (MFR)-1.2;

a weight ratio ((A-1):(B-1)) between said ethylene/α-olefin copolymer(A-1) and said high-pressure radical polymerization low-densitypolyethylene (B-1) being in the range of 98:2 to 70:30.
 2. The ethylenecopolymer composition of claim 1 wherein the ethylene/α-olefin (A-1)contains ethylene units in an amount from 55 to 99% by weight andα-olefin units in an amount of from 1 to 45% by weight.
 3. The ethylenecopolymer composition of claim 1 wherein the ethylene/α-olefin copolymer(A-1) contains unsaturated bonds in an amount of not more than 0.5 per1000 carbon atoms and less than 1 per molecule of the copolymer.
 4. Theethylene copolymer composition of claim 1 wherein the high-pressureradical polymerization low-density polyethylene (B-1) has a density inthe range of from 0.910 to 0.930 g/cm³.
 5. The ethylene copolymercomposition of claim 1 wherein the weight ratio of (A-1) to (B-1) is inthe range of from 98:2 to 80:20.
 6. The ethylene copolymer compositionof claim 1 wherein the ethylene/α-olefin copolymer (A-1) is obtained bycopolymerizing ethylene and α-olefin having 3 to 20 carbon atoms in thepresence of an olefin polymerization catalyst formed from (a) ametallocene compound, (b) an organoaluminum oxy-compound, (c) a carrier,and, optionally, (d) an organoaluminum compound catalyst component. 7.The ethylene copolymer composition of claim 1 wherein theethylene/α-olefin copolymer (A-1) is obtained by copolymerizing ethyleneand α-olefin having 3 to 20 carbon atoms in the presence of an olefinpolymerization catalyst formed from (a) transition metal compoundcatalyst component represented by the following formula (I) or (II), (b)an organoaluminum oxy-compound, (c) a carrier, and, optionally, (d) anorganoaluminum compound catalyst component;

    MKL.sup.1.sub.x-2                                          (I)

    ML.sup.2.sub.x                                             (II)

wherein M is a transition metal atom selected from Group IVB of theperiodic table, K is a bidentate ligand formed by bonding the same ordifferent indenyl groups, substituted indenyl groups or their partiallyhydrogenated products through a lower alkylene group, L¹ is ahydrocarbon group of 1 to 12 carbon atoms, an alkoxy group, an aryloxygroup, a halogen atom, a trialkylsilyl group or a hydrogen atom, L² is aligand coordinating to the transition metal atom, at least two of L² aresubstituted cyclopentadienyl group having 2-5 substituted groupsselected from methyl group and ethyl group, and L² other than thesubstituted cyclopentadienyl group is a hydrocarbon group of 1 to 12carbon atoms, an alkoxy group, an aryloxy group, a halogen atom, atrialkylsilyl group or a hydrogen atom, and X is a valence of thetransition metal M.